Research ArticleKey Blasting Parameters for Deep-Hole Excavation in anUnderground Tunnel of Phosphorite Mine

Xiu-wei Chai1 Sha-sha Shi 1 Yao-feng Yan2 Jian-guo Li1 and Long Zhang3

1School of Resources amp Safety Engineering Wuhan Institute of Technology Hubei Wuhan 430074 China2School of Civil Engineering and Architecture Wuhan University of Technology Hubei Wuhan 430074 China3College of Water Resource amp Hydropower Sichuan University Sichuan Chengdu 610000 China

Correspondence should be addressed to Sha-sha Shi 1943378655qqcom

Received 9 September 2019 Accepted 18 November 2019 Published 5 December 2019

Academic Editor Chongchong Qi

Copyright copy 2019 Xiu-wei Chai et al is is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Ever increasingmine production capacity andmechanized operations enable advanced drilling equipment to be widely adopted inunderground mines In order to achieve satisfactory blasting performance in tunnel advance there is a critical need to optimizethe blasting technique tomatch the large deep-hole drilling capability In this study through theoretical analysis of tunnel blastingthe layout of cutting holes was found to be the key factor controlling the blasting performance e deep-hole cutting effect wasfirst investigated by analyzing the influence of the free surface of a hollow hole using the fluid-structure interaction modelingmethod in ANSYSLS-DYNA en the rock dynamic evolution processes of blasting using a double-cavity grooving and a four-cavity grooving were compared and analyzed towards an understanding of the influence of the spacing and layout of cutting holeson the blasting performance e comparison results show that four empty hole cut layouts yield larger effective free surface thanthat of the two empty hole cut layoutsis is because larger compensation space for breaking of rock and expansion of gas is moreconducive to improving the energy utilization rate of explosives and thus improving the blasting performance and the footage ofcyclic blasting e results indicated that the blasting performance can be improved by reserving reasonable compensation spacein the grooving area

1 Introduction

Mining development is an indispensable part of Chinarsquoseconomic construction which has made great contributionsto the economy Tunneling blasting is the main constructionmethod in the mine construction and production processe success of excavation will directly affect the blastingeffect of roadway excavation In the blasting process ofstraight cut the existence of empty holes can create goodconditions for rock crushing in the cavity erefore op-timizing and improving the cut method is the main methodto improve the blasting effect of mine tunneling

In view of the construction of mines and tunnels underdifferent geological conditions many scholars have carriedout a lot of research on the blasting of the trench anddiscussed the influence of cutting mode cutting parameters

cutting diameter and charging mode on blasting effect[1ndash6] Shan et al [7] proposed that the main cut and theworking face have an angle while the auxiliary cut wasperpendicular to the free face Man et al [8] carried out theblasting test of face cutting mode in the Beishan pit ex-ploration facility project in Gansue straight-eye groovingmethod is better than the single wedge-shaped grooving andcomposite wedge-shaped grooving method e peripheralhole has a higher half porosity Yang et al [9] used numericalcalculation and field test to study the double wedge deep-hole blasting which provided reference for rock tunnelingengineering Ma et al [10] simplified the design process ofkey parameters of roof cutting blasting with mathematicalanalysis method and determined the key indexes that affectthe blasting design Zhang [11] ranked the factors affectingthe blasting vibration of the gutter by gray correlation

HindawiAdvances in Civil EngineeringVolume 2019 Article ID 4924382 9 pageshttpsdoiorg10115520194924382

analysis so as to optimize the design of the hollow holeblasting Wang et al [12] analyzed the explosive stress field ofthe first-order cut hole by numerical simulation and proposedthat the increase of the central diameter empty hole made thestress wave peak value around the empty holemore than twiceas much as that in the rock mass without empty hole Zuoet al [13] used high-speed photography to observe thethrowing process and shape of the blasting rock mass underdifferent hole diameters and proposed that the volume of thecavity was related to the diameter of the hole Lin et al [14 15]studied the law of the cavity formation of the gutter and foundthat the rock would be ejected under the action of the gasgenerated by the high-pressure explosion

In the above research the mechanism and applicationof empty holes are discussed more but the research on theinfluence of the number of empty holes on the blastingeffect is less In practice the number and location of emptyholes are closely related to the blasting effect It is of greatengineering significance to study the influence of thenumber of empty holes on the blasting effect of cutting Inthis paper the Houping phosphorite mine was used anengineering example Firstly the fluid-structure interactionmodeling method in the finite element software ANSYSLS-DYNA [16] was applied to analyze the effect of the freesurface effect of the hollow hole in the hollow hole on theeffect of deep-hole grooving en the comparative analysisof the dynamic evolution process of the cavity in thedouble-cavity gutter and the four-cavity gutter and theinfluence of the size and distribution of the free surface onthe blasting effect were studied Finally the gutteringtechnology for improving the deep-hole blasting ofphosphate rock was optimized

2 Analysis of Empty Hole Effect

e empty holes not only provide initial space for rockblasting but also convert the stress state around the rock asa free surface After the detonation of the charging holethe shock wave generated by the explosion quickly at-tenuates into a stress wave [17] When the stress wave istransmitted to the empty hole the reflection phenomenonwill occur leading to the increase of the stress wave at thewall of the empty hole namely the stress concentrationeffect of the empty hole [18ndash21] ereby the rock iscracked broken and thrown in the direction of the chargehole e blasting effect is achieved e stress wavegenerated by the two-hole explosion has a stress peakattenuation expression of

σr p0r

r01113888 1113889

minus α

σθ minus λdσr

⎧⎪⎪⎪⎪⎨

⎪⎪⎪⎪⎩

(1)

where σr is the radial stress of a certain point in the rockmass MPa σθ is the tangential stress of the explosion at apoint in the rock MPa p0 is the initial pressure acting on thehole wall after the explosion of the explosive MPa r0 is the

radius of the blasthole m r is the distance from a point in therock to the center of the blasthole m and α is the stress waveattenuation coefficient λd is the dynamic side stresscoefficient

It can be seen from Figure 1 that when the stress wave istransmitted to the wall of an empty hole the stress of the wallwill be greater than that in the case of no empty hole at isto say the more the number of empty holes is the greater theguiding effect and expansion space provided by rockfragmentation

3 Simulation and Analysis

rough the theoretical analysis of void effect the me-chanical parameters of rock are measured by using thetriaxial apparatus in a laboratory e ANSYSLS-DYNAfinite element program is used to simulate the blastingprocess of deep cut in tunnel excavation and the blastingcharacteristics of deep cut in tunnel excavation are ana-lyzed e field test results are verified and compared withthe simulation results in order to optimize and improve thecutting technology of deep-hole blasting in phosphatemine

31 Establishment of NumericalModel Using the LS-DYNAfinite element program a three-dimensional model was builtusing cmgus e model length was 70 cm width was70 cm height was 450 cm and the diameter of the blastholewas 40mm Figure 2 shows the numerical model corre-sponding to four empty holes and two empty holes

32 Material Constitutive Equations and Parameters emodel includes three materials explosive rock and airamong which the plugging material is rock e anisotropicelastoplastic model in the LS-DYNA material model librarywas selected for the rock element For air the NULL modelwas used For explosives the MAT HIGH EXPLOSIVE_BURN model [22] and the JWL state equation were usedand the expression is

P A 1 minusω

R1V1113888 1113889e

minus R1V+ B 1 minus

ωR2V

1113888 1113889eminus R2V

+ωE0

V (2)

where P is the pressure MPa V is the volume change andR1 R2 ω B and A are all material constants

Dynamite air and rock mechanics parameters areshown in Table 1

33 Results and Discussion

331 Effect of Cavity Cutting on Cavity FormationSpatial and temporal evolution of surrounding rock stress oftwo and four cut holes are shown in Figures 3 and 4

e cut blasting process can be clearly seen in Figure 3At the moment of 240 μs the cut area turns red and thestress wave effect of the explosive is the largest and it affectsthe whole area At 280 μs the stress waves of the first andthird rows of charge holes are superimposed along the hole

2 Advances in Civil Engineering

Figure 2 Numerical calculation model

Table 1 Material parameters

Explosiveparameters

Densityρ(gcm3)

Detonation speedD Pressure PCJ Bulk modulus K Shear modulus

G mdash

10 036 324E minus 02 mdash

Air parameter Density Cutoff pressurepc

Dynamic viscositycoefficient MU

Relative volumeTEROD

Elastic modulusYM

Poissonrsquosratio PR

12929E minus 03

Rock mechanicsparameters

Bulk weight c

(gcm3)Elastic modulus

E (GPa) Poissonrsquos ratio Uniaxialcompression (MPa)

Tensile strength(MPa)

Cohesion C(MPa)

273 55 036 65 45 45

θ

Charge hole

L

R1R2

σθ σθσr

σr

Empty hole

Figure 1 Analysis of stress concentration effect of voids

LS-DYNA user inputTime = 2399Contours of effective stress(v-m)min = 232816e ndash 10 at elem232214max = 0000600001 at elem302104Section min = 812156e ndash 05near node277166Section max = 00006near node363671

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

2328e ndash 10

Fringe levels

(a)

LS-DYNA user inputTime = 280Contours of effective stress(v-m)min = 0 at elem238188max = 0000600001 at elem356065Section min = 835469e ndash 05near node269329Section max = 00006near node322174

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

0000e + 00

Fringe levels

(b)

Figure 3 Continued

Advances in Civil Engineering 3

coring line causing the rock in the hole coring line to breakfirst and the rock in the hole area begins to rupture by thestress wave At 420 μs it can be seen from the figure that theviolent compression phenomenon occurred in the explo-sive blasting process the rocks near the upper and lowerrows of charge holes are deeply damaged and the gutterarea is formed well Since the circumference of the twoholes in the center is not enough to provide enough spacefor the cavities of the eight charging holes the rock mass inthe gutter area has not ejected during the gutter process At1820 μs the shape of the cut area has been preliminarilyformed

e spatial and temporal evolution cloud diagram ofthe effective stress in the four holes in Figure 4 shows that

at 260 μs the stress superposition between the charginghole and the void hole is strengthened and under theguidance of the void hole the surrounding rock begins tocrack along the hole connection center At 280 μs momentthe two charge holes in the middle have the greatest degreeof rupture and the holes on the connecting line of thecharge holes are ruptured It is proved that both chargeholes and holes will rupture along the connecting line of thecharge holes under the action of explosive load At 400 μs itis also observed that the rock in the area near the holesbreaks along the core line of the holes e upper and lowerholes are deeply damaged and the cutting area is well formedIt can be seen that at 1879 μs the core rock mass of the four-hole cut is all taken out and only some rock masses around

LS-DYNA user inputTime = 25997Contours of effective stress(v-m)min = 525318e ndash 10 at elem2667886max = 0000600001 at elem415529Section min = 839604e ndash 05near node345016Section max = 00006near node333731

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

5253e ndash 10

Fringe levels

(a)

LS-DYNA user inputTime = 27997Contours of effective stress(v-m)min = 0 at elem273508max = 0000600001 at elem290733Section min = 666589e ndash 05near node326539Section max = 00006near node329474

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

0000e + 00

Fringe levels

(b)

LS-DYNA user inputTime = 39996Contours of effective stress(v-m)min = 0 at elem273236max = 00006 at elem273257Section min = 179332e ndash 05near node326737Section max = 00006near node345912

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

0000e + 00

Fringe levels

(c)

LS-DYNA user inputTime = 18799Contours of effective stress(v-m)min = 0 at elem293211max = 00006 at elem308961Section min = 144732e ndash 05near node405982Section max = 00006near node330266

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

0000e + 00

Fringe levels

(d)

Figure 4 Temporal and spatial evolutionary cloud diagram of effective stress of four holes (a) 260 μs (b) 280 μs (c) 400 μs (d) 1879 μs

LS-DYNA user inputTime = 41999Contours of effective stress(v-m)min = 266171e ndash 08 at elem233447max = 00006 at elem315295Section min = 75e ndash 05near node326728Section max = 00006near node328192

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

2662e ndash 08

Fringe levels

(c)

LS-DYNA user inputTime = 18199Contours of effective stress(v-m)min = 0 at elem274464max = 00006 at elem248565Section min = 383389e ndash 05near node367334Section max = 00006near node288071

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

0000e + 00

Fringe levels

(d)

Figure 3 Spatiotemporal evolutionary cloud diagram of effective stress of two holes (a) 240 μs (b) 280 μs (c) 420 μs (d) 1820 μs

4 Advances in Civil Engineering

the hole are not stripped of the parent rock if two chargingholes are added on the periphery of the charge the explosivewill destroy the rock break the rock away from the rock walland will generate more cutting space

It can be seen that the empty hole has a great impact onthe formation of the cavity On the one hand it can providesufficient compensation space for the rock breakage in thecut area on the other hand it can serve as directionalfracture between two holes two explosive holes and the holeand the explosive hole

332 Effect of Different Hole Cutting on Stress Distribution ofSurrounding Rock of Charge Hole e stress distribution ofthe surrounding rock of the charge hole under differenthollow hole gutter schemes is shown in Figure 5

It can be seen from Figures 5(a) and 5(b) that thetensile stress and compressive stress of the loading sectionare characterized by stress jump and oscillation As awhole the area of relatively high compressive stress is nearthe charging center In Figure 5(a) the compressive stressof the loading section of the four holes decreases from503MPa to 368MPa and a sudden change occurs in thecompressive stress value of unit nos 7 and 8 which in-creases from 337MPa to 508MPa ere is a stressanomaly which is the result of the combined action ofstress wave and explosive gas In Figure 5(b) the stressvalue of several elements in the four holes is 0 comparedwith that in the two holes because the rock is in a crushingstate under the action of high stress which was related tothe superposition effect of stress wave in the propagationprocess e average compressive stress at the charginglength unit of the four empty holes was 4465MPa whilethe average pressure at the two empty holes was35075MPa Obviously the compressive stress of the fourholes was more advantageous than that of the two holeswhich was conducive to broken rock mass e tensilestress of two holes oscillates violently but that of fourholes maintains a low level which was related to rationalcharging

According to Figure 5(c) at the early stage of theplugging section the maximum compressive stress of thefour holes is 473MPa and the pressure is large beforereaching the plugging medium and finally decreases to18MPa e compressive stress of two holes and four holesshows a decreasing trend which indicates that the prop-agation of the stress wave in the later stage of explosivereaction does not have enough energy to maintain but thecompressive stress of four holes has obvious advantages Ascan be seen from Figure 5(d) the tensile stress value of thetwo holes does not appear at the same time with thecompressive stress value but the hysterical maximumcompressive stress appears Similarly the pressure value atunit nos 7 and 8 decreases from 46MPa to 29MPa becausethe sharp reduction of compressive stress leads to thereduction of Poissonrsquos effect of the unit and the accom-panying tensile stress To sum up the rock near the freesurface of the plugging section is dominated by tensilestress failure e stress value does not show a decreasing

trend of attenuation and the type of action is different atdifferent plugging locations

It can be seen from Figure 5(e) that the maximumcompressive stress of the two holes and four holes in thebottom section of the hole appeared in the contact areabetween explosive and rock and the maximum compressivestress of the four holes was 503MPa larger than the 407MPaof the two holes As can be seen from Figure 5(f) the tensilestress value at unit nos 6 7 and 8 of the two empty holes was0 which was caused by the explosion stress wave near theinitiation point of these three units and the compressionrock of explosive gas so the compressive stress was in-creased and the tensile stress was 0 From the size of theelement it can be inferred that the compressive stress andtensile stress of the rock 50 cm away from the bottom of thehole are both large which were not effective for tunnelblasting and will seriously affect the next construction op-eration and blasting effecte tensile stress of the four holeswas the result of stress wave action in Sections 1ndash4 of unitnumber where the tensile stress value at fourth unit was4MPa less than that on both sides which was related to thesuperposition factor of the stress wave e tensile stress atelement number 6 was 0 because the element is near theinitiation point From the stress data it can be seen that thefour-hole cutting blasting scheme has more advantages It ismore conducive to improve circular footage and blastingeffect

4 Application Analysis

41 Site Conditions and Scheme e phosphorite mine inHouping member of Shukongping mining area is a sedi-mentary phosphate block rock deposit which occurs in thefirst section of Sinian Doushantuo formation and is a hiddenore body e occurrence of the ore layer is stratiformconsistent with the occurrence of the rock layer and thewhole is monoclinal structure slightly undulating andrelatively gentle occurrence

In order to study the physical and mechanical prop-erties of mine rock the theoretical analysis and numericalsimulation method were used to optimize the design todetermine the cutting scheme of straight hole with fourholes e cutting scheme of four empty straight holes onthe project site is shown in Figure 6 and the relevantblasting parameters are shown in Table 2

42 Analysis of Application Effect e comparison betweenthe original project blasting and the four-hole blastingscheme at the engineering site is shown in Figure 7

In general the average unit consumption of explosivesused in the two-hole blasting scheme is 2054 kgm3 whichis higher than the rated standard of 186 kgm3 for driftexcavation blasting e average footage of single cycleexcavation is 2966m the utilization rate of blast holes isnot more than 80 the depth of residual holes is up to60 cm and the blasting effect and tunnel forming are poorIn the four-hole blasting scheme the average unit ex-plosive consumption is 1809 kgm3 the average footage of

Advances in Civil Engineering 5

single cycle excavation is about 34m and the utilizationrate of blast holes is up to 92 From the scenes two emptyhole and four empty hole blasting effect data withoutchanging the total charge and the number of blast holesthe blasting effect of the four holes is obviously better thanthat of the two holes and images taken from the

representative can be seen that the rock mass under thefour-hole blasting scheme is relatively uniform From theuniform fragmentation it can be seen that the hole dis-tribution mode and millisecond blasting time of thesection are reasonable which is convenient for shovelingand transportation

1 2 3 4 5 6 7 8

Com

pres

sive s

tres

s (M

Pa)

0

100

200

300

400

500

600

Two holesFour holes

(a)

1 2 3 4 5 6 7 80

20

40

60

80

100

120

140

Tens

ile st

ress

(MPa

)

Two holesFour holes

(b)

Com

pres

sive s

tres

s (M

Pa)

1 2 3 4 5 6 7 80

100

200

300

400

500

Two holesFour holes

(c)

1 2 3 4 5 6 7 80

50

100

150

200

Tens

ile st

ress

(MPa

)

Two holesFour holes

(d)

Com

pres

sive s

tres

s (M

Pa)

1 2 3 4 5 6 7 80

100

200

300

400

500

600

Two holesFour holes

(e)

1 2 3 4 5 6 7 8

20

40

60

80

100

Tens

ile st

ress

(MPa

)

Two holesFour holes

0

(f )

Figure 5 Stress curve of each part of the blasthole (a) Pressure stress in the charging section (b) Pulling stress in the charging section (c)Blocking section compressive stress (d) Pulling section tensile stress (e) Rock compressive stress at the bottom of the blasthole (f ) Rocktensile stress at the bottom of the blasthole

6 Advances in Civil Engineering

Table 2 Explosion parameters of the four-hole slotting scheme

Gun hole nameParameter

Number of holes Single hole charge (kg) Detonator sectionSlot hole 10 (12 7sim4) 3 MS1Auxiliary hole 18 (15sim32) 25 HS6Peripheral hole 15 (33sim47) 21 HS10Nos 3ndash6 are large empty holes e detonator segments 1-2 7-8 and 9ndash14 are respectively MS1 MS9 and HS2 e detonator segments from 15 to 18 areHS3 19 to 22 are HS5 23 to 26 are HS6 27 to 29 are HS7 and 30 to 32 are HS8 e detonator segments of 33sim43 are HS9 while those of 44sim47 are HS10

4 12

13 17 25 381826

2061422

312

5

28 37161115

29

192423

31 36

453534

27

3344

43 30

42

41

47 40 39 46

7 8

10 9

21

32

Figure 6 Four-hole blasting scheme (the numbers in the figure represent the hole number)

(a)

Figure 7 Continued

Advances in Civil Engineering 7

5 Conclusion

In this paper it is theoretically analyzed that the existence ofempty holes can provide initial space for rock blasting and thenthe formation process of the cavity in the cutting area is sim-ulated by numerical simulation Finally the following conclu-sions are obtained by combining with the site blasting test

(1) Compared with two holes the arrangement of the fourholes optimizes the cutting area of the blasting and thesufficient empty hole space provides sufficient ex-pansion compensation space for rock blasting

(2) e existence of voids and explosive holes changesthe stress state of the gutter region and the complexdynamic effects are generated under the action ofcharge explosion e preferential fracture in thestress concentration area reflects the stress concen-tration of the pores

(3) For the blasting of the gutter area the four emptyholes play the role of energy constraint and guidanceto the charge of the inner layer and free surface to theexternal charge which jointly promote the formationof the cutting area

(4) emain causes of the formation of the tunnel cavityare the compressive stress and explosive gas of thedeep-hole cutting blasting and the tensile stress hasno obvious superiority in this process

In this study the influence of the cutting mode on theblasting effect of tunnel excavation gives that the four-holecutting mode is better than the two-hole cutting mode Inorder to prove the advantages of the scheme it should beapplied to the roadway with different cross-section sizes tofurther verify the advantages of its blasting effect

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e support from the National Natural Science Foundationof China (Grant no 51709257) and Science and TechnologyResearch Project of Hubei Education Department (Grant noD20171506) is sincerely appreciated

References

[1] J B Martino and N A Chandler ldquoExcavation-induceddamage studies at the underground research laboratoryrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 8 pp 1413ndash1426 2004

[2] M Ramulu A K Chakraborty and T G Sitharam ldquoDamageassessment of basaltic rock mass due to repeated blasting in arailway tunnelling projectmdasha case studyrdquo Tunnelling andUnderground Space Technology vol 24 no 2 pp 208ndash2212009

[3] J Yang W Lu Y Hu M Chen and P Yan ldquoNumericalsimulation of rock mass damage evolution during deep-buried tunnel excavation by drill and blastrdquo Rock Mechanicsand Rock Engineering vol 48 no 5 pp 2045ndash2059 2015

[4] L Zhang J-H Hu X-L Wang and L Zhao ldquoOptimizationof stope structural parameters based on mathews stabilitygraph probability modelrdquo Advances in Civil Engineeringvol 2018 Article ID 1754328 7 pages 2018

[5] K Soroush Y Mehdi and E Arash ldquoTrend analysis andcomparison of basic parameters for tunnel blast designmodelsrdquo International Journal of Mining Science and Tech-nology vol 25 no 4 pp 595ndash599 2015

[6] D Guo H Wang X Li et al ldquoNumerical analysis on ex-pansion chamber process of large hollow hole cut blasting inyixin coal minerdquo Blasting vol 34 no 2 pp 9ndash14 2017

[7] R Shan B Huang W Gao et al ldquoCase studies of newtechnology application of quasi-parallel cut blasting in rockroadway drivagerdquo Journal of RockMechanics and Engineeringvol 30 no 2 pp 224ndash232 2011

(b)

Figure 7 Comparison of on-site blasting effects (a) Original plan blasting effect (b) Four-hole blasting effect

8 Advances in Civil Engineering

[8] K Man X Liu J Wang and X Wang ldquoBlasting energyanalysis of the different cutting methodsrdquo Shock and Vi-bration vol 2018 Article ID 9419018 13 pages 2018

[9] G Yang L Jiang and R Yang ldquoInvestigation of cut blastingwith duplex wedge deep holesrdquo Journal of China University ofMining amp Technology vol 42 no 5 pp 755ndash760 2013

[10] X Ma M He J Sun H Wang X Liu and E Zhen ldquoNeuralnetwork of roof cutting blasting parameters based on mineswith different roof conditionsrdquo Energies vol 11 no 12p 3468 2018

[11] X Zhang ldquoGrey correlation analysis of influence factors ofblasting vibration with straight hollow hole cuttingrdquo Mu-nicipal Engineering Technology vol 36 no 3 pp 138ndash1402018

[12] H Wang Z Qi and Y Zhao ldquoNumerical analysis and ap-plication of large-diameter cavity parallel cut blasting stressfield in vertical shaftrdquo Chinese Journal of Rock Mechanics andEngineering vol 34 no S1 pp 3223ndash3229 2015

[13] J Zuo R Yang C Xiao et al ldquoModel test of empty hole cutblasting in coal mine rock drivagerdquo Journal of Mining Scienceand Technology vol 3 no 4 pp 335ndash341 2018

[14] D Lin and S Chen ldquoExperimental and theoretical study ofparallel hole cut blasting with cavityrdquo Rock and Soil Me-chanics vol 26 no 3 pp 479ndash483 2005

[15] D Lin Research on Size Effect of Empty Hole in HorizontalRoadway Cut Blasting amp Accumulating Characteristic ofSurrounding Rock Damage Caused by Frequently BlastingVibration Central South University Changsha China 2006

[16] X-F Pan and Y-F Mao ldquoe numerical simulation of shaftexcavation blasting cavity expansion process based onANSYSLS-DYNArdquo Coal Mine Blasting vol 108 no 4pp 19ndash24 2014

[17] J W Swegle and S W Attaway ldquoOn the feasibility of usingsmoothed particle hydrodynamics for underwater explosioncalculationsrdquo Computational Mechanics vol 17 no 3pp 151ndash168 1995

[18] S H Cho and K Kaneko ldquoInfluence of the applied pressurewaveform on the dynamic fracture processes in rockrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 5 pp 771ndash784 2004

[19] Y Liu Z Zhou J Li et al ldquoeoretical and experimentalstudy on empty hole effect in tunnel cut blastingrdquoMetal Minevol 368 no 2 pp 12ndash14 2007

[20] S Wang and Y Wang ldquoEmpty hole effect under three-borehole directional blasting loadrdquo Science and Technologyand Engineering vol 16 no 35 2016

[21] Q Chen H Li X Xiang et al ldquoResearch and application ofempty hole effect under blasting loadingrdquo Journal of ChinaCoal Society vol 41 no 11 pp 2749ndash2755 2016

[22] G Fu X Tan and F Gao ldquoStudy on rational blasting depth oftunnel passing under through airport runwayrdquo ChineseJournal of Underground Space and Engineering vol 8pp 1148ndash1152 2012

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

Figure 2 Numerical calculation model

Table 1 Material parameters

Explosiveparameters

Densityρ(gcm3)

Detonation speedD Pressure PCJ Bulk modulus K Shear modulus

G mdash

10 036 324E minus 02 mdash

Air parameter Density Cutoff pressurepc

Dynamic viscositycoefficient MU

Relative volumeTEROD

Elastic modulusYM

Poissonrsquosratio PR

12929E minus 03

Rock mechanicsparameters

Bulk weight c

(gcm3)Elastic modulus

E (GPa) Poissonrsquos ratio Uniaxialcompression (MPa)

Tensile strength(MPa)

Cohesion C(MPa)

273 55 036 65 45 45

θ

Charge hole

L

R1R2

σθ σθσr

σr

Empty hole

Figure 1 Analysis of stress concentration effect of voids

LS-DYNA user inputTime = 2399Contours of effective stress(v-m)min = 232816e ndash 10 at elem232214max = 0000600001 at elem302104Section min = 812156e ndash 05near node277166Section max = 00006near node363671

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

2328e ndash 10

Fringe levels

(a)

LS-DYNA user inputTime = 280Contours of effective stress(v-m)min = 0 at elem238188max = 0000600001 at elem356065Section min = 835469e ndash 05near node269329Section max = 00006near node322174

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

0000e + 00

Fringe levels

(b)

Figure 3 Continued

Advances in Civil Engineering 3

coring line causing the rock in the hole coring line to breakfirst and the rock in the hole area begins to rupture by thestress wave At 420 μs it can be seen from the figure that theviolent compression phenomenon occurred in the explo-sive blasting process the rocks near the upper and lowerrows of charge holes are deeply damaged and the gutterarea is formed well Since the circumference of the twoholes in the center is not enough to provide enough spacefor the cavities of the eight charging holes the rock mass inthe gutter area has not ejected during the gutter process At1820 μs the shape of the cut area has been preliminarilyformed

e spatial and temporal evolution cloud diagram ofthe effective stress in the four holes in Figure 4 shows that

at 260 μs the stress superposition between the charginghole and the void hole is strengthened and under theguidance of the void hole the surrounding rock begins tocrack along the hole connection center At 280 μs momentthe two charge holes in the middle have the greatest degreeof rupture and the holes on the connecting line of thecharge holes are ruptured It is proved that both chargeholes and holes will rupture along the connecting line of thecharge holes under the action of explosive load At 400 μs itis also observed that the rock in the area near the holesbreaks along the core line of the holes e upper and lowerholes are deeply damaged and the cutting area is well formedIt can be seen that at 1879 μs the core rock mass of the four-hole cut is all taken out and only some rock masses around

LS-DYNA user inputTime = 25997Contours of effective stress(v-m)min = 525318e ndash 10 at elem2667886max = 0000600001 at elem415529Section min = 839604e ndash 05near node345016Section max = 00006near node333731

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

5253e ndash 10

Fringe levels

(a)

LS-DYNA user inputTime = 27997Contours of effective stress(v-m)min = 0 at elem273508max = 0000600001 at elem290733Section min = 666589e ndash 05near node326539Section max = 00006near node329474

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

0000e + 00

Fringe levels

(b)

LS-DYNA user inputTime = 39996Contours of effective stress(v-m)min = 0 at elem273236max = 00006 at elem273257Section min = 179332e ndash 05near node326737Section max = 00006near node345912

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

0000e + 00

Fringe levels

(c)

LS-DYNA user inputTime = 18799Contours of effective stress(v-m)min = 0 at elem293211max = 00006 at elem308961Section min = 144732e ndash 05near node405982Section max = 00006near node330266

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

0000e + 00

Fringe levels

(d)

Figure 4 Temporal and spatial evolutionary cloud diagram of effective stress of four holes (a) 260 μs (b) 280 μs (c) 400 μs (d) 1879 μs

LS-DYNA user inputTime = 41999Contours of effective stress(v-m)min = 266171e ndash 08 at elem233447max = 00006 at elem315295Section min = 75e ndash 05near node326728Section max = 00006near node328192

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

2662e ndash 08

Fringe levels

(c)

LS-DYNA user inputTime = 18199Contours of effective stress(v-m)min = 0 at elem274464max = 00006 at elem248565Section min = 383389e ndash 05near node367334Section max = 00006near node288071

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

0000e + 00

Fringe levels

(d)

Figure 3 Spatiotemporal evolutionary cloud diagram of effective stress of two holes (a) 240 μs (b) 280 μs (c) 420 μs (d) 1820 μs

4 Advances in Civil Engineering

the hole are not stripped of the parent rock if two chargingholes are added on the periphery of the charge the explosivewill destroy the rock break the rock away from the rock walland will generate more cutting space

It can be seen that the empty hole has a great impact onthe formation of the cavity On the one hand it can providesufficient compensation space for the rock breakage in thecut area on the other hand it can serve as directionalfracture between two holes two explosive holes and the holeand the explosive hole

332 Effect of Different Hole Cutting on Stress Distribution ofSurrounding Rock of Charge Hole e stress distribution ofthe surrounding rock of the charge hole under differenthollow hole gutter schemes is shown in Figure 5

It can be seen from Figures 5(a) and 5(b) that thetensile stress and compressive stress of the loading sectionare characterized by stress jump and oscillation As awhole the area of relatively high compressive stress is nearthe charging center In Figure 5(a) the compressive stressof the loading section of the four holes decreases from503MPa to 368MPa and a sudden change occurs in thecompressive stress value of unit nos 7 and 8 which in-creases from 337MPa to 508MPa ere is a stressanomaly which is the result of the combined action ofstress wave and explosive gas In Figure 5(b) the stressvalue of several elements in the four holes is 0 comparedwith that in the two holes because the rock is in a crushingstate under the action of high stress which was related tothe superposition effect of stress wave in the propagationprocess e average compressive stress at the charginglength unit of the four empty holes was 4465MPa whilethe average pressure at the two empty holes was35075MPa Obviously the compressive stress of the fourholes was more advantageous than that of the two holeswhich was conducive to broken rock mass e tensilestress of two holes oscillates violently but that of fourholes maintains a low level which was related to rationalcharging

According to Figure 5(c) at the early stage of theplugging section the maximum compressive stress of thefour holes is 473MPa and the pressure is large beforereaching the plugging medium and finally decreases to18MPa e compressive stress of two holes and four holesshows a decreasing trend which indicates that the prop-agation of the stress wave in the later stage of explosivereaction does not have enough energy to maintain but thecompressive stress of four holes has obvious advantages Ascan be seen from Figure 5(d) the tensile stress value of thetwo holes does not appear at the same time with thecompressive stress value but the hysterical maximumcompressive stress appears Similarly the pressure value atunit nos 7 and 8 decreases from 46MPa to 29MPa becausethe sharp reduction of compressive stress leads to thereduction of Poissonrsquos effect of the unit and the accom-panying tensile stress To sum up the rock near the freesurface of the plugging section is dominated by tensilestress failure e stress value does not show a decreasing

trend of attenuation and the type of action is different atdifferent plugging locations

It can be seen from Figure 5(e) that the maximumcompressive stress of the two holes and four holes in thebottom section of the hole appeared in the contact areabetween explosive and rock and the maximum compressivestress of the four holes was 503MPa larger than the 407MPaof the two holes As can be seen from Figure 5(f) the tensilestress value at unit nos 6 7 and 8 of the two empty holes was0 which was caused by the explosion stress wave near theinitiation point of these three units and the compressionrock of explosive gas so the compressive stress was in-creased and the tensile stress was 0 From the size of theelement it can be inferred that the compressive stress andtensile stress of the rock 50 cm away from the bottom of thehole are both large which were not effective for tunnelblasting and will seriously affect the next construction op-eration and blasting effecte tensile stress of the four holeswas the result of stress wave action in Sections 1ndash4 of unitnumber where the tensile stress value at fourth unit was4MPa less than that on both sides which was related to thesuperposition factor of the stress wave e tensile stress atelement number 6 was 0 because the element is near theinitiation point From the stress data it can be seen that thefour-hole cutting blasting scheme has more advantages It ismore conducive to improve circular footage and blastingeffect

4 Application Analysis

41 Site Conditions and Scheme e phosphorite mine inHouping member of Shukongping mining area is a sedi-mentary phosphate block rock deposit which occurs in thefirst section of Sinian Doushantuo formation and is a hiddenore body e occurrence of the ore layer is stratiformconsistent with the occurrence of the rock layer and thewhole is monoclinal structure slightly undulating andrelatively gentle occurrence

In order to study the physical and mechanical prop-erties of mine rock the theoretical analysis and numericalsimulation method were used to optimize the design todetermine the cutting scheme of straight hole with fourholes e cutting scheme of four empty straight holes onthe project site is shown in Figure 6 and the relevantblasting parameters are shown in Table 2

42 Analysis of Application Effect e comparison betweenthe original project blasting and the four-hole blastingscheme at the engineering site is shown in Figure 7

In general the average unit consumption of explosivesused in the two-hole blasting scheme is 2054 kgm3 whichis higher than the rated standard of 186 kgm3 for driftexcavation blasting e average footage of single cycleexcavation is 2966m the utilization rate of blast holes isnot more than 80 the depth of residual holes is up to60 cm and the blasting effect and tunnel forming are poorIn the four-hole blasting scheme the average unit ex-plosive consumption is 1809 kgm3 the average footage of

Advances in Civil Engineering 5

single cycle excavation is about 34m and the utilizationrate of blast holes is up to 92 From the scenes two emptyhole and four empty hole blasting effect data withoutchanging the total charge and the number of blast holesthe blasting effect of the four holes is obviously better thanthat of the two holes and images taken from the

representative can be seen that the rock mass under thefour-hole blasting scheme is relatively uniform From theuniform fragmentation it can be seen that the hole dis-tribution mode and millisecond blasting time of thesection are reasonable which is convenient for shovelingand transportation

1 2 3 4 5 6 7 8

Com

pres

sive s

tres

s (M

Pa)

0

100

200

300

400

500

600

Two holesFour holes

(a)

1 2 3 4 5 6 7 80

20

40

60

80

100

120

140

Tens

ile st

ress

(MPa

)

Two holesFour holes

(b)

Com

pres

sive s

tres

s (M

Pa)

1 2 3 4 5 6 7 80

100

200

300

400

500

Two holesFour holes

(c)

1 2 3 4 5 6 7 80

50

100

150

200

Tens

ile st

ress

(MPa

)

Two holesFour holes

(d)

Com

pres

sive s

tres

s (M

Pa)

1 2 3 4 5 6 7 80

100

200

300

400

500

600

Two holesFour holes

(e)

1 2 3 4 5 6 7 8

20

40

60

80

100

Tens

ile st

ress

(MPa

)

Two holesFour holes

0

(f )

Figure 5 Stress curve of each part of the blasthole (a) Pressure stress in the charging section (b) Pulling stress in the charging section (c)Blocking section compressive stress (d) Pulling section tensile stress (e) Rock compressive stress at the bottom of the blasthole (f ) Rocktensile stress at the bottom of the blasthole

6 Advances in Civil Engineering

Table 2 Explosion parameters of the four-hole slotting scheme

Gun hole nameParameter

Number of holes Single hole charge (kg) Detonator sectionSlot hole 10 (12 7sim4) 3 MS1Auxiliary hole 18 (15sim32) 25 HS6Peripheral hole 15 (33sim47) 21 HS10Nos 3ndash6 are large empty holes e detonator segments 1-2 7-8 and 9ndash14 are respectively MS1 MS9 and HS2 e detonator segments from 15 to 18 areHS3 19 to 22 are HS5 23 to 26 are HS6 27 to 29 are HS7 and 30 to 32 are HS8 e detonator segments of 33sim43 are HS9 while those of 44sim47 are HS10

4 12

13 17 25 381826

2061422

312

5

28 37161115

29

192423

31 36

453534

27

3344

43 30

42

41

47 40 39 46

7 8

10 9

21

32

Figure 6 Four-hole blasting scheme (the numbers in the figure represent the hole number)

(a)

Figure 7 Continued

Advances in Civil Engineering 7

5 Conclusion

In this paper it is theoretically analyzed that the existence ofempty holes can provide initial space for rock blasting and thenthe formation process of the cavity in the cutting area is sim-ulated by numerical simulation Finally the following conclu-sions are obtained by combining with the site blasting test

(1) Compared with two holes the arrangement of the fourholes optimizes the cutting area of the blasting and thesufficient empty hole space provides sufficient ex-pansion compensation space for rock blasting

(2) e existence of voids and explosive holes changesthe stress state of the gutter region and the complexdynamic effects are generated under the action ofcharge explosion e preferential fracture in thestress concentration area reflects the stress concen-tration of the pores

(3) For the blasting of the gutter area the four emptyholes play the role of energy constraint and guidanceto the charge of the inner layer and free surface to theexternal charge which jointly promote the formationof the cutting area

(4) emain causes of the formation of the tunnel cavityare the compressive stress and explosive gas of thedeep-hole cutting blasting and the tensile stress hasno obvious superiority in this process

In this study the influence of the cutting mode on theblasting effect of tunnel excavation gives that the four-holecutting mode is better than the two-hole cutting mode Inorder to prove the advantages of the scheme it should beapplied to the roadway with different cross-section sizes tofurther verify the advantages of its blasting effect

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e support from the National Natural Science Foundationof China (Grant no 51709257) and Science and TechnologyResearch Project of Hubei Education Department (Grant noD20171506) is sincerely appreciated

References

[1] J B Martino and N A Chandler ldquoExcavation-induceddamage studies at the underground research laboratoryrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 8 pp 1413ndash1426 2004

[2] M Ramulu A K Chakraborty and T G Sitharam ldquoDamageassessment of basaltic rock mass due to repeated blasting in arailway tunnelling projectmdasha case studyrdquo Tunnelling andUnderground Space Technology vol 24 no 2 pp 208ndash2212009

[3] J Yang W Lu Y Hu M Chen and P Yan ldquoNumericalsimulation of rock mass damage evolution during deep-buried tunnel excavation by drill and blastrdquo Rock Mechanicsand Rock Engineering vol 48 no 5 pp 2045ndash2059 2015

[4] L Zhang J-H Hu X-L Wang and L Zhao ldquoOptimizationof stope structural parameters based on mathews stabilitygraph probability modelrdquo Advances in Civil Engineeringvol 2018 Article ID 1754328 7 pages 2018

[5] K Soroush Y Mehdi and E Arash ldquoTrend analysis andcomparison of basic parameters for tunnel blast designmodelsrdquo International Journal of Mining Science and Tech-nology vol 25 no 4 pp 595ndash599 2015

[6] D Guo H Wang X Li et al ldquoNumerical analysis on ex-pansion chamber process of large hollow hole cut blasting inyixin coal minerdquo Blasting vol 34 no 2 pp 9ndash14 2017

[7] R Shan B Huang W Gao et al ldquoCase studies of newtechnology application of quasi-parallel cut blasting in rockroadway drivagerdquo Journal of RockMechanics and Engineeringvol 30 no 2 pp 224ndash232 2011

(b)

Figure 7 Comparison of on-site blasting effects (a) Original plan blasting effect (b) Four-hole blasting effect

8 Advances in Civil Engineering

[8] K Man X Liu J Wang and X Wang ldquoBlasting energyanalysis of the different cutting methodsrdquo Shock and Vi-bration vol 2018 Article ID 9419018 13 pages 2018

[9] G Yang L Jiang and R Yang ldquoInvestigation of cut blastingwith duplex wedge deep holesrdquo Journal of China University ofMining amp Technology vol 42 no 5 pp 755ndash760 2013

[10] X Ma M He J Sun H Wang X Liu and E Zhen ldquoNeuralnetwork of roof cutting blasting parameters based on mineswith different roof conditionsrdquo Energies vol 11 no 12p 3468 2018

[11] X Zhang ldquoGrey correlation analysis of influence factors ofblasting vibration with straight hollow hole cuttingrdquo Mu-nicipal Engineering Technology vol 36 no 3 pp 138ndash1402018

[12] H Wang Z Qi and Y Zhao ldquoNumerical analysis and ap-plication of large-diameter cavity parallel cut blasting stressfield in vertical shaftrdquo Chinese Journal of Rock Mechanics andEngineering vol 34 no S1 pp 3223ndash3229 2015

[13] J Zuo R Yang C Xiao et al ldquoModel test of empty hole cutblasting in coal mine rock drivagerdquo Journal of Mining Scienceand Technology vol 3 no 4 pp 335ndash341 2018

[14] D Lin and S Chen ldquoExperimental and theoretical study ofparallel hole cut blasting with cavityrdquo Rock and Soil Me-chanics vol 26 no 3 pp 479ndash483 2005

[15] D Lin Research on Size Effect of Empty Hole in HorizontalRoadway Cut Blasting amp Accumulating Characteristic ofSurrounding Rock Damage Caused by Frequently BlastingVibration Central South University Changsha China 2006

[16] X-F Pan and Y-F Mao ldquoe numerical simulation of shaftexcavation blasting cavity expansion process based onANSYSLS-DYNArdquo Coal Mine Blasting vol 108 no 4pp 19ndash24 2014

[17] J W Swegle and S W Attaway ldquoOn the feasibility of usingsmoothed particle hydrodynamics for underwater explosioncalculationsrdquo Computational Mechanics vol 17 no 3pp 151ndash168 1995

[18] S H Cho and K Kaneko ldquoInfluence of the applied pressurewaveform on the dynamic fracture processes in rockrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 5 pp 771ndash784 2004

[19] Y Liu Z Zhou J Li et al ldquoeoretical and experimentalstudy on empty hole effect in tunnel cut blastingrdquoMetal Minevol 368 no 2 pp 12ndash14 2007

[20] S Wang and Y Wang ldquoEmpty hole effect under three-borehole directional blasting loadrdquo Science and Technologyand Engineering vol 16 no 35 2016

[21] Q Chen H Li X Xiang et al ldquoResearch and application ofempty hole effect under blasting loadingrdquo Journal of ChinaCoal Society vol 41 no 11 pp 2749ndash2755 2016

[22] G Fu X Tan and F Gao ldquoStudy on rational blasting depth oftunnel passing under through airport runwayrdquo ChineseJournal of Underground Space and Engineering vol 8pp 1148ndash1152 2012

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

coring line causing the rock in the hole coring line to breakfirst and the rock in the hole area begins to rupture by thestress wave At 420 μs it can be seen from the figure that theviolent compression phenomenon occurred in the explo-sive blasting process the rocks near the upper and lowerrows of charge holes are deeply damaged and the gutterarea is formed well Since the circumference of the twoholes in the center is not enough to provide enough spacefor the cavities of the eight charging holes the rock mass inthe gutter area has not ejected during the gutter process At1820 μs the shape of the cut area has been preliminarilyformed

e spatial and temporal evolution cloud diagram ofthe effective stress in the four holes in Figure 4 shows that

at 260 μs the stress superposition between the charginghole and the void hole is strengthened and under theguidance of the void hole the surrounding rock begins tocrack along the hole connection center At 280 μs momentthe two charge holes in the middle have the greatest degreeof rupture and the holes on the connecting line of thecharge holes are ruptured It is proved that both chargeholes and holes will rupture along the connecting line of thecharge holes under the action of explosive load At 400 μs itis also observed that the rock in the area near the holesbreaks along the core line of the holes e upper and lowerholes are deeply damaged and the cutting area is well formedIt can be seen that at 1879 μs the core rock mass of the four-hole cut is all taken out and only some rock masses around

LS-DYNA user inputTime = 25997Contours of effective stress(v-m)min = 525318e ndash 10 at elem2667886max = 0000600001 at elem415529Section min = 839604e ndash 05near node345016Section max = 00006near node333731

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

5253e ndash 10

Fringe levels

(a)

LS-DYNA user inputTime = 27997Contours of effective stress(v-m)min = 0 at elem273508max = 0000600001 at elem290733Section min = 666589e ndash 05near node326539Section max = 00006near node329474

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

0000e + 00

Fringe levels

(b)

LS-DYNA user inputTime = 39996Contours of effective stress(v-m)min = 0 at elem273236max = 00006 at elem273257Section min = 179332e ndash 05near node326737Section max = 00006near node345912

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

0000e + 00

Fringe levels

(c)

LS-DYNA user inputTime = 18799Contours of effective stress(v-m)min = 0 at elem293211max = 00006 at elem308961Section min = 144732e ndash 05near node405982Section max = 00006near node330266

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

0000e + 00

Fringe levels

(d)

Figure 4 Temporal and spatial evolutionary cloud diagram of effective stress of four holes (a) 260 μs (b) 280 μs (c) 400 μs (d) 1879 μs

LS-DYNA user inputTime = 41999Contours of effective stress(v-m)min = 266171e ndash 08 at elem233447max = 00006 at elem315295Section min = 75e ndash 05near node326728Section max = 00006near node328192

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

2662e ndash 08

Fringe levels

(c)

LS-DYNA user inputTime = 18199Contours of effective stress(v-m)min = 0 at elem274464max = 00006 at elem248565Section min = 383389e ndash 05near node367334Section max = 00006near node288071

6000e ndash 04

5400e ndash 04

4800e ndash 04

4200e ndash 04

3600e ndash 04

3000e ndash 04

2400e ndash 04

1800e ndash 04

1200e ndash 04

6000e ndash 05

0000e + 00

Fringe levels

(d)

Figure 3 Spatiotemporal evolutionary cloud diagram of effective stress of two holes (a) 240 μs (b) 280 μs (c) 420 μs (d) 1820 μs

4 Advances in Civil Engineering

the hole are not stripped of the parent rock if two chargingholes are added on the periphery of the charge the explosivewill destroy the rock break the rock away from the rock walland will generate more cutting space

It can be seen that the empty hole has a great impact onthe formation of the cavity On the one hand it can providesufficient compensation space for the rock breakage in thecut area on the other hand it can serve as directionalfracture between two holes two explosive holes and the holeand the explosive hole

332 Effect of Different Hole Cutting on Stress Distribution ofSurrounding Rock of Charge Hole e stress distribution ofthe surrounding rock of the charge hole under differenthollow hole gutter schemes is shown in Figure 5

It can be seen from Figures 5(a) and 5(b) that thetensile stress and compressive stress of the loading sectionare characterized by stress jump and oscillation As awhole the area of relatively high compressive stress is nearthe charging center In Figure 5(a) the compressive stressof the loading section of the four holes decreases from503MPa to 368MPa and a sudden change occurs in thecompressive stress value of unit nos 7 and 8 which in-creases from 337MPa to 508MPa ere is a stressanomaly which is the result of the combined action ofstress wave and explosive gas In Figure 5(b) the stressvalue of several elements in the four holes is 0 comparedwith that in the two holes because the rock is in a crushingstate under the action of high stress which was related tothe superposition effect of stress wave in the propagationprocess e average compressive stress at the charginglength unit of the four empty holes was 4465MPa whilethe average pressure at the two empty holes was35075MPa Obviously the compressive stress of the fourholes was more advantageous than that of the two holeswhich was conducive to broken rock mass e tensilestress of two holes oscillates violently but that of fourholes maintains a low level which was related to rationalcharging

According to Figure 5(c) at the early stage of theplugging section the maximum compressive stress of thefour holes is 473MPa and the pressure is large beforereaching the plugging medium and finally decreases to18MPa e compressive stress of two holes and four holesshows a decreasing trend which indicates that the prop-agation of the stress wave in the later stage of explosivereaction does not have enough energy to maintain but thecompressive stress of four holes has obvious advantages Ascan be seen from Figure 5(d) the tensile stress value of thetwo holes does not appear at the same time with thecompressive stress value but the hysterical maximumcompressive stress appears Similarly the pressure value atunit nos 7 and 8 decreases from 46MPa to 29MPa becausethe sharp reduction of compressive stress leads to thereduction of Poissonrsquos effect of the unit and the accom-panying tensile stress To sum up the rock near the freesurface of the plugging section is dominated by tensilestress failure e stress value does not show a decreasing

trend of attenuation and the type of action is different atdifferent plugging locations

It can be seen from Figure 5(e) that the maximumcompressive stress of the two holes and four holes in thebottom section of the hole appeared in the contact areabetween explosive and rock and the maximum compressivestress of the four holes was 503MPa larger than the 407MPaof the two holes As can be seen from Figure 5(f) the tensilestress value at unit nos 6 7 and 8 of the two empty holes was0 which was caused by the explosion stress wave near theinitiation point of these three units and the compressionrock of explosive gas so the compressive stress was in-creased and the tensile stress was 0 From the size of theelement it can be inferred that the compressive stress andtensile stress of the rock 50 cm away from the bottom of thehole are both large which were not effective for tunnelblasting and will seriously affect the next construction op-eration and blasting effecte tensile stress of the four holeswas the result of stress wave action in Sections 1ndash4 of unitnumber where the tensile stress value at fourth unit was4MPa less than that on both sides which was related to thesuperposition factor of the stress wave e tensile stress atelement number 6 was 0 because the element is near theinitiation point From the stress data it can be seen that thefour-hole cutting blasting scheme has more advantages It ismore conducive to improve circular footage and blastingeffect

4 Application Analysis

41 Site Conditions and Scheme e phosphorite mine inHouping member of Shukongping mining area is a sedi-mentary phosphate block rock deposit which occurs in thefirst section of Sinian Doushantuo formation and is a hiddenore body e occurrence of the ore layer is stratiformconsistent with the occurrence of the rock layer and thewhole is monoclinal structure slightly undulating andrelatively gentle occurrence

In order to study the physical and mechanical prop-erties of mine rock the theoretical analysis and numericalsimulation method were used to optimize the design todetermine the cutting scheme of straight hole with fourholes e cutting scheme of four empty straight holes onthe project site is shown in Figure 6 and the relevantblasting parameters are shown in Table 2

42 Analysis of Application Effect e comparison betweenthe original project blasting and the four-hole blastingscheme at the engineering site is shown in Figure 7

In general the average unit consumption of explosivesused in the two-hole blasting scheme is 2054 kgm3 whichis higher than the rated standard of 186 kgm3 for driftexcavation blasting e average footage of single cycleexcavation is 2966m the utilization rate of blast holes isnot more than 80 the depth of residual holes is up to60 cm and the blasting effect and tunnel forming are poorIn the four-hole blasting scheme the average unit ex-plosive consumption is 1809 kgm3 the average footage of

Advances in Civil Engineering 5

single cycle excavation is about 34m and the utilizationrate of blast holes is up to 92 From the scenes two emptyhole and four empty hole blasting effect data withoutchanging the total charge and the number of blast holesthe blasting effect of the four holes is obviously better thanthat of the two holes and images taken from the

representative can be seen that the rock mass under thefour-hole blasting scheme is relatively uniform From theuniform fragmentation it can be seen that the hole dis-tribution mode and millisecond blasting time of thesection are reasonable which is convenient for shovelingand transportation

1 2 3 4 5 6 7 8

Com

pres

sive s

tres

s (M

Pa)

0

100

200

300

400

500

600

Two holesFour holes

(a)

1 2 3 4 5 6 7 80

20

40

60

80

100

120

140

Tens

ile st

ress

(MPa

)

Two holesFour holes

(b)

Com

pres

sive s

tres

s (M

Pa)

1 2 3 4 5 6 7 80

100

200

300

400

500

Two holesFour holes

(c)

1 2 3 4 5 6 7 80

50

100

150

200

Tens

ile st

ress

(MPa

)

Two holesFour holes

(d)

Com

pres

sive s

tres

s (M

Pa)

1 2 3 4 5 6 7 80

100

200

300

400

500

600

Two holesFour holes

(e)

1 2 3 4 5 6 7 8

20

40

60

80

100

Tens

ile st

ress

(MPa

)

Two holesFour holes

0

(f )

Figure 5 Stress curve of each part of the blasthole (a) Pressure stress in the charging section (b) Pulling stress in the charging section (c)Blocking section compressive stress (d) Pulling section tensile stress (e) Rock compressive stress at the bottom of the blasthole (f ) Rocktensile stress at the bottom of the blasthole

6 Advances in Civil Engineering

Table 2 Explosion parameters of the four-hole slotting scheme

Gun hole nameParameter

Number of holes Single hole charge (kg) Detonator sectionSlot hole 10 (12 7sim4) 3 MS1Auxiliary hole 18 (15sim32) 25 HS6Peripheral hole 15 (33sim47) 21 HS10Nos 3ndash6 are large empty holes e detonator segments 1-2 7-8 and 9ndash14 are respectively MS1 MS9 and HS2 e detonator segments from 15 to 18 areHS3 19 to 22 are HS5 23 to 26 are HS6 27 to 29 are HS7 and 30 to 32 are HS8 e detonator segments of 33sim43 are HS9 while those of 44sim47 are HS10

4 12

13 17 25 381826

2061422

312

5

28 37161115

29

192423

31 36

453534

27

3344

43 30

42

41

47 40 39 46

7 8

10 9

21

32

Figure 6 Four-hole blasting scheme (the numbers in the figure represent the hole number)

(a)

Figure 7 Continued

Advances in Civil Engineering 7

5 Conclusion

In this paper it is theoretically analyzed that the existence ofempty holes can provide initial space for rock blasting and thenthe formation process of the cavity in the cutting area is sim-ulated by numerical simulation Finally the following conclu-sions are obtained by combining with the site blasting test

(1) Compared with two holes the arrangement of the fourholes optimizes the cutting area of the blasting and thesufficient empty hole space provides sufficient ex-pansion compensation space for rock blasting

(2) e existence of voids and explosive holes changesthe stress state of the gutter region and the complexdynamic effects are generated under the action ofcharge explosion e preferential fracture in thestress concentration area reflects the stress concen-tration of the pores

(3) For the blasting of the gutter area the four emptyholes play the role of energy constraint and guidanceto the charge of the inner layer and free surface to theexternal charge which jointly promote the formationof the cutting area

(4) emain causes of the formation of the tunnel cavityare the compressive stress and explosive gas of thedeep-hole cutting blasting and the tensile stress hasno obvious superiority in this process

In this study the influence of the cutting mode on theblasting effect of tunnel excavation gives that the four-holecutting mode is better than the two-hole cutting mode Inorder to prove the advantages of the scheme it should beapplied to the roadway with different cross-section sizes tofurther verify the advantages of its blasting effect

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e support from the National Natural Science Foundationof China (Grant no 51709257) and Science and TechnologyResearch Project of Hubei Education Department (Grant noD20171506) is sincerely appreciated

References

[1] J B Martino and N A Chandler ldquoExcavation-induceddamage studies at the underground research laboratoryrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 8 pp 1413ndash1426 2004

[2] M Ramulu A K Chakraborty and T G Sitharam ldquoDamageassessment of basaltic rock mass due to repeated blasting in arailway tunnelling projectmdasha case studyrdquo Tunnelling andUnderground Space Technology vol 24 no 2 pp 208ndash2212009

[3] J Yang W Lu Y Hu M Chen and P Yan ldquoNumericalsimulation of rock mass damage evolution during deep-buried tunnel excavation by drill and blastrdquo Rock Mechanicsand Rock Engineering vol 48 no 5 pp 2045ndash2059 2015

[4] L Zhang J-H Hu X-L Wang and L Zhao ldquoOptimizationof stope structural parameters based on mathews stabilitygraph probability modelrdquo Advances in Civil Engineeringvol 2018 Article ID 1754328 7 pages 2018

[5] K Soroush Y Mehdi and E Arash ldquoTrend analysis andcomparison of basic parameters for tunnel blast designmodelsrdquo International Journal of Mining Science and Tech-nology vol 25 no 4 pp 595ndash599 2015

[6] D Guo H Wang X Li et al ldquoNumerical analysis on ex-pansion chamber process of large hollow hole cut blasting inyixin coal minerdquo Blasting vol 34 no 2 pp 9ndash14 2017

[7] R Shan B Huang W Gao et al ldquoCase studies of newtechnology application of quasi-parallel cut blasting in rockroadway drivagerdquo Journal of RockMechanics and Engineeringvol 30 no 2 pp 224ndash232 2011

(b)

Figure 7 Comparison of on-site blasting effects (a) Original plan blasting effect (b) Four-hole blasting effect

8 Advances in Civil Engineering

[8] K Man X Liu J Wang and X Wang ldquoBlasting energyanalysis of the different cutting methodsrdquo Shock and Vi-bration vol 2018 Article ID 9419018 13 pages 2018

[9] G Yang L Jiang and R Yang ldquoInvestigation of cut blastingwith duplex wedge deep holesrdquo Journal of China University ofMining amp Technology vol 42 no 5 pp 755ndash760 2013

[10] X Ma M He J Sun H Wang X Liu and E Zhen ldquoNeuralnetwork of roof cutting blasting parameters based on mineswith different roof conditionsrdquo Energies vol 11 no 12p 3468 2018

[11] X Zhang ldquoGrey correlation analysis of influence factors ofblasting vibration with straight hollow hole cuttingrdquo Mu-nicipal Engineering Technology vol 36 no 3 pp 138ndash1402018

[12] H Wang Z Qi and Y Zhao ldquoNumerical analysis and ap-plication of large-diameter cavity parallel cut blasting stressfield in vertical shaftrdquo Chinese Journal of Rock Mechanics andEngineering vol 34 no S1 pp 3223ndash3229 2015

[13] J Zuo R Yang C Xiao et al ldquoModel test of empty hole cutblasting in coal mine rock drivagerdquo Journal of Mining Scienceand Technology vol 3 no 4 pp 335ndash341 2018

[14] D Lin and S Chen ldquoExperimental and theoretical study ofparallel hole cut blasting with cavityrdquo Rock and Soil Me-chanics vol 26 no 3 pp 479ndash483 2005

[15] D Lin Research on Size Effect of Empty Hole in HorizontalRoadway Cut Blasting amp Accumulating Characteristic ofSurrounding Rock Damage Caused by Frequently BlastingVibration Central South University Changsha China 2006

[16] X-F Pan and Y-F Mao ldquoe numerical simulation of shaftexcavation blasting cavity expansion process based onANSYSLS-DYNArdquo Coal Mine Blasting vol 108 no 4pp 19ndash24 2014

[17] J W Swegle and S W Attaway ldquoOn the feasibility of usingsmoothed particle hydrodynamics for underwater explosioncalculationsrdquo Computational Mechanics vol 17 no 3pp 151ndash168 1995

[18] S H Cho and K Kaneko ldquoInfluence of the applied pressurewaveform on the dynamic fracture processes in rockrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 5 pp 771ndash784 2004

[19] Y Liu Z Zhou J Li et al ldquoeoretical and experimentalstudy on empty hole effect in tunnel cut blastingrdquoMetal Minevol 368 no 2 pp 12ndash14 2007

[20] S Wang and Y Wang ldquoEmpty hole effect under three-borehole directional blasting loadrdquo Science and Technologyand Engineering vol 16 no 35 2016

[21] Q Chen H Li X Xiang et al ldquoResearch and application ofempty hole effect under blasting loadingrdquo Journal of ChinaCoal Society vol 41 no 11 pp 2749ndash2755 2016

[22] G Fu X Tan and F Gao ldquoStudy on rational blasting depth oftunnel passing under through airport runwayrdquo ChineseJournal of Underground Space and Engineering vol 8pp 1148ndash1152 2012

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

the hole are not stripped of the parent rock if two chargingholes are added on the periphery of the charge the explosivewill destroy the rock break the rock away from the rock walland will generate more cutting space

It can be seen that the empty hole has a great impact onthe formation of the cavity On the one hand it can providesufficient compensation space for the rock breakage in thecut area on the other hand it can serve as directionalfracture between two holes two explosive holes and the holeand the explosive hole

332 Effect of Different Hole Cutting on Stress Distribution ofSurrounding Rock of Charge Hole e stress distribution ofthe surrounding rock of the charge hole under differenthollow hole gutter schemes is shown in Figure 5

It can be seen from Figures 5(a) and 5(b) that thetensile stress and compressive stress of the loading sectionare characterized by stress jump and oscillation As awhole the area of relatively high compressive stress is nearthe charging center In Figure 5(a) the compressive stressof the loading section of the four holes decreases from503MPa to 368MPa and a sudden change occurs in thecompressive stress value of unit nos 7 and 8 which in-creases from 337MPa to 508MPa ere is a stressanomaly which is the result of the combined action ofstress wave and explosive gas In Figure 5(b) the stressvalue of several elements in the four holes is 0 comparedwith that in the two holes because the rock is in a crushingstate under the action of high stress which was related tothe superposition effect of stress wave in the propagationprocess e average compressive stress at the charginglength unit of the four empty holes was 4465MPa whilethe average pressure at the two empty holes was35075MPa Obviously the compressive stress of the fourholes was more advantageous than that of the two holeswhich was conducive to broken rock mass e tensilestress of two holes oscillates violently but that of fourholes maintains a low level which was related to rationalcharging

According to Figure 5(c) at the early stage of theplugging section the maximum compressive stress of thefour holes is 473MPa and the pressure is large beforereaching the plugging medium and finally decreases to18MPa e compressive stress of two holes and four holesshows a decreasing trend which indicates that the prop-agation of the stress wave in the later stage of explosivereaction does not have enough energy to maintain but thecompressive stress of four holes has obvious advantages Ascan be seen from Figure 5(d) the tensile stress value of thetwo holes does not appear at the same time with thecompressive stress value but the hysterical maximumcompressive stress appears Similarly the pressure value atunit nos 7 and 8 decreases from 46MPa to 29MPa becausethe sharp reduction of compressive stress leads to thereduction of Poissonrsquos effect of the unit and the accom-panying tensile stress To sum up the rock near the freesurface of the plugging section is dominated by tensilestress failure e stress value does not show a decreasing

trend of attenuation and the type of action is different atdifferent plugging locations

It can be seen from Figure 5(e) that the maximumcompressive stress of the two holes and four holes in thebottom section of the hole appeared in the contact areabetween explosive and rock and the maximum compressivestress of the four holes was 503MPa larger than the 407MPaof the two holes As can be seen from Figure 5(f) the tensilestress value at unit nos 6 7 and 8 of the two empty holes was0 which was caused by the explosion stress wave near theinitiation point of these three units and the compressionrock of explosive gas so the compressive stress was in-creased and the tensile stress was 0 From the size of theelement it can be inferred that the compressive stress andtensile stress of the rock 50 cm away from the bottom of thehole are both large which were not effective for tunnelblasting and will seriously affect the next construction op-eration and blasting effecte tensile stress of the four holeswas the result of stress wave action in Sections 1ndash4 of unitnumber where the tensile stress value at fourth unit was4MPa less than that on both sides which was related to thesuperposition factor of the stress wave e tensile stress atelement number 6 was 0 because the element is near theinitiation point From the stress data it can be seen that thefour-hole cutting blasting scheme has more advantages It ismore conducive to improve circular footage and blastingeffect

4 Application Analysis

41 Site Conditions and Scheme e phosphorite mine inHouping member of Shukongping mining area is a sedi-mentary phosphate block rock deposit which occurs in thefirst section of Sinian Doushantuo formation and is a hiddenore body e occurrence of the ore layer is stratiformconsistent with the occurrence of the rock layer and thewhole is monoclinal structure slightly undulating andrelatively gentle occurrence

In order to study the physical and mechanical prop-erties of mine rock the theoretical analysis and numericalsimulation method were used to optimize the design todetermine the cutting scheme of straight hole with fourholes e cutting scheme of four empty straight holes onthe project site is shown in Figure 6 and the relevantblasting parameters are shown in Table 2

42 Analysis of Application Effect e comparison betweenthe original project blasting and the four-hole blastingscheme at the engineering site is shown in Figure 7

In general the average unit consumption of explosivesused in the two-hole blasting scheme is 2054 kgm3 whichis higher than the rated standard of 186 kgm3 for driftexcavation blasting e average footage of single cycleexcavation is 2966m the utilization rate of blast holes isnot more than 80 the depth of residual holes is up to60 cm and the blasting effect and tunnel forming are poorIn the four-hole blasting scheme the average unit ex-plosive consumption is 1809 kgm3 the average footage of

Advances in Civil Engineering 5

single cycle excavation is about 34m and the utilizationrate of blast holes is up to 92 From the scenes two emptyhole and four empty hole blasting effect data withoutchanging the total charge and the number of blast holesthe blasting effect of the four holes is obviously better thanthat of the two holes and images taken from the

representative can be seen that the rock mass under thefour-hole blasting scheme is relatively uniform From theuniform fragmentation it can be seen that the hole dis-tribution mode and millisecond blasting time of thesection are reasonable which is convenient for shovelingand transportation

1 2 3 4 5 6 7 8

Com

pres

sive s

tres

s (M

Pa)

0

100

200

300

400

500

600

Two holesFour holes

(a)

1 2 3 4 5 6 7 80

20

40

60

80

100

120

140

Tens

ile st

ress

(MPa

)

Two holesFour holes

(b)

Com

pres

sive s

tres

s (M

Pa)

1 2 3 4 5 6 7 80

100

200

300

400

500

Two holesFour holes

(c)

1 2 3 4 5 6 7 80

50

100

150

200

Tens

ile st

ress

(MPa

)

Two holesFour holes

(d)

Com

pres

sive s

tres

s (M

Pa)

1 2 3 4 5 6 7 80

100

200

300

400

500

600

Two holesFour holes

(e)

1 2 3 4 5 6 7 8

20

40

60

80

100

Tens

ile st

ress

(MPa

)

Two holesFour holes

0

(f )

Figure 5 Stress curve of each part of the blasthole (a) Pressure stress in the charging section (b) Pulling stress in the charging section (c)Blocking section compressive stress (d) Pulling section tensile stress (e) Rock compressive stress at the bottom of the blasthole (f ) Rocktensile stress at the bottom of the blasthole

6 Advances in Civil Engineering

Table 2 Explosion parameters of the four-hole slotting scheme

Gun hole nameParameter

Number of holes Single hole charge (kg) Detonator sectionSlot hole 10 (12 7sim4) 3 MS1Auxiliary hole 18 (15sim32) 25 HS6Peripheral hole 15 (33sim47) 21 HS10Nos 3ndash6 are large empty holes e detonator segments 1-2 7-8 and 9ndash14 are respectively MS1 MS9 and HS2 e detonator segments from 15 to 18 areHS3 19 to 22 are HS5 23 to 26 are HS6 27 to 29 are HS7 and 30 to 32 are HS8 e detonator segments of 33sim43 are HS9 while those of 44sim47 are HS10

4 12

13 17 25 381826

2061422

312

5

28 37161115

29

192423

31 36

453534

27

3344

43 30

42

41

47 40 39 46

7 8

10 9

21

32

Figure 6 Four-hole blasting scheme (the numbers in the figure represent the hole number)

(a)

Figure 7 Continued

Advances in Civil Engineering 7

5 Conclusion

In this paper it is theoretically analyzed that the existence ofempty holes can provide initial space for rock blasting and thenthe formation process of the cavity in the cutting area is sim-ulated by numerical simulation Finally the following conclu-sions are obtained by combining with the site blasting test

(1) Compared with two holes the arrangement of the fourholes optimizes the cutting area of the blasting and thesufficient empty hole space provides sufficient ex-pansion compensation space for rock blasting

(2) e existence of voids and explosive holes changesthe stress state of the gutter region and the complexdynamic effects are generated under the action ofcharge explosion e preferential fracture in thestress concentration area reflects the stress concen-tration of the pores

(3) For the blasting of the gutter area the four emptyholes play the role of energy constraint and guidanceto the charge of the inner layer and free surface to theexternal charge which jointly promote the formationof the cutting area

(4) emain causes of the formation of the tunnel cavityare the compressive stress and explosive gas of thedeep-hole cutting blasting and the tensile stress hasno obvious superiority in this process

In this study the influence of the cutting mode on theblasting effect of tunnel excavation gives that the four-holecutting mode is better than the two-hole cutting mode Inorder to prove the advantages of the scheme it should beapplied to the roadway with different cross-section sizes tofurther verify the advantages of its blasting effect

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e support from the National Natural Science Foundationof China (Grant no 51709257) and Science and TechnologyResearch Project of Hubei Education Department (Grant noD20171506) is sincerely appreciated

References

[1] J B Martino and N A Chandler ldquoExcavation-induceddamage studies at the underground research laboratoryrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 8 pp 1413ndash1426 2004

[2] M Ramulu A K Chakraborty and T G Sitharam ldquoDamageassessment of basaltic rock mass due to repeated blasting in arailway tunnelling projectmdasha case studyrdquo Tunnelling andUnderground Space Technology vol 24 no 2 pp 208ndash2212009

[3] J Yang W Lu Y Hu M Chen and P Yan ldquoNumericalsimulation of rock mass damage evolution during deep-buried tunnel excavation by drill and blastrdquo Rock Mechanicsand Rock Engineering vol 48 no 5 pp 2045ndash2059 2015

[4] L Zhang J-H Hu X-L Wang and L Zhao ldquoOptimizationof stope structural parameters based on mathews stabilitygraph probability modelrdquo Advances in Civil Engineeringvol 2018 Article ID 1754328 7 pages 2018

[5] K Soroush Y Mehdi and E Arash ldquoTrend analysis andcomparison of basic parameters for tunnel blast designmodelsrdquo International Journal of Mining Science and Tech-nology vol 25 no 4 pp 595ndash599 2015

[6] D Guo H Wang X Li et al ldquoNumerical analysis on ex-pansion chamber process of large hollow hole cut blasting inyixin coal minerdquo Blasting vol 34 no 2 pp 9ndash14 2017

[7] R Shan B Huang W Gao et al ldquoCase studies of newtechnology application of quasi-parallel cut blasting in rockroadway drivagerdquo Journal of RockMechanics and Engineeringvol 30 no 2 pp 224ndash232 2011

(b)

Figure 7 Comparison of on-site blasting effects (a) Original plan blasting effect (b) Four-hole blasting effect

8 Advances in Civil Engineering

[8] K Man X Liu J Wang and X Wang ldquoBlasting energyanalysis of the different cutting methodsrdquo Shock and Vi-bration vol 2018 Article ID 9419018 13 pages 2018

[9] G Yang L Jiang and R Yang ldquoInvestigation of cut blastingwith duplex wedge deep holesrdquo Journal of China University ofMining amp Technology vol 42 no 5 pp 755ndash760 2013

[10] X Ma M He J Sun H Wang X Liu and E Zhen ldquoNeuralnetwork of roof cutting blasting parameters based on mineswith different roof conditionsrdquo Energies vol 11 no 12p 3468 2018

[11] X Zhang ldquoGrey correlation analysis of influence factors ofblasting vibration with straight hollow hole cuttingrdquo Mu-nicipal Engineering Technology vol 36 no 3 pp 138ndash1402018

[12] H Wang Z Qi and Y Zhao ldquoNumerical analysis and ap-plication of large-diameter cavity parallel cut blasting stressfield in vertical shaftrdquo Chinese Journal of Rock Mechanics andEngineering vol 34 no S1 pp 3223ndash3229 2015

[13] J Zuo R Yang C Xiao et al ldquoModel test of empty hole cutblasting in coal mine rock drivagerdquo Journal of Mining Scienceand Technology vol 3 no 4 pp 335ndash341 2018

[14] D Lin and S Chen ldquoExperimental and theoretical study ofparallel hole cut blasting with cavityrdquo Rock and Soil Me-chanics vol 26 no 3 pp 479ndash483 2005

[15] D Lin Research on Size Effect of Empty Hole in HorizontalRoadway Cut Blasting amp Accumulating Characteristic ofSurrounding Rock Damage Caused by Frequently BlastingVibration Central South University Changsha China 2006

[16] X-F Pan and Y-F Mao ldquoe numerical simulation of shaftexcavation blasting cavity expansion process based onANSYSLS-DYNArdquo Coal Mine Blasting vol 108 no 4pp 19ndash24 2014

[17] J W Swegle and S W Attaway ldquoOn the feasibility of usingsmoothed particle hydrodynamics for underwater explosioncalculationsrdquo Computational Mechanics vol 17 no 3pp 151ndash168 1995

[18] S H Cho and K Kaneko ldquoInfluence of the applied pressurewaveform on the dynamic fracture processes in rockrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 5 pp 771ndash784 2004

[19] Y Liu Z Zhou J Li et al ldquoeoretical and experimentalstudy on empty hole effect in tunnel cut blastingrdquoMetal Minevol 368 no 2 pp 12ndash14 2007

[20] S Wang and Y Wang ldquoEmpty hole effect under three-borehole directional blasting loadrdquo Science and Technologyand Engineering vol 16 no 35 2016

[21] Q Chen H Li X Xiang et al ldquoResearch and application ofempty hole effect under blasting loadingrdquo Journal of ChinaCoal Society vol 41 no 11 pp 2749ndash2755 2016

[22] G Fu X Tan and F Gao ldquoStudy on rational blasting depth oftunnel passing under through airport runwayrdquo ChineseJournal of Underground Space and Engineering vol 8pp 1148ndash1152 2012

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

single cycle excavation is about 34m and the utilizationrate of blast holes is up to 92 From the scenes two emptyhole and four empty hole blasting effect data withoutchanging the total charge and the number of blast holesthe blasting effect of the four holes is obviously better thanthat of the two holes and images taken from the

representative can be seen that the rock mass under thefour-hole blasting scheme is relatively uniform From theuniform fragmentation it can be seen that the hole dis-tribution mode and millisecond blasting time of thesection are reasonable which is convenient for shovelingand transportation

1 2 3 4 5 6 7 8

Com

pres

sive s

tres

s (M

Pa)

0

100

200

300

400

500

600

Two holesFour holes

(a)

1 2 3 4 5 6 7 80

20

40

60

80

100

120

140

Tens

ile st

ress

(MPa

)

Two holesFour holes

(b)

Com

pres

sive s

tres

s (M

Pa)

1 2 3 4 5 6 7 80

100

200

300

400

500

Two holesFour holes

(c)

1 2 3 4 5 6 7 80

50

100

150

200

Tens

ile st

ress

(MPa

)

Two holesFour holes

(d)

Com

pres

sive s

tres

s (M

Pa)

1 2 3 4 5 6 7 80

100

200

300

400

500

600

Two holesFour holes

(e)

1 2 3 4 5 6 7 8

20

40

60

80

100

Tens

ile st

ress

(MPa

)

Two holesFour holes

0

(f )

Figure 5 Stress curve of each part of the blasthole (a) Pressure stress in the charging section (b) Pulling stress in the charging section (c)Blocking section compressive stress (d) Pulling section tensile stress (e) Rock compressive stress at the bottom of the blasthole (f ) Rocktensile stress at the bottom of the blasthole

6 Advances in Civil Engineering

Table 2 Explosion parameters of the four-hole slotting scheme

Gun hole nameParameter

Number of holes Single hole charge (kg) Detonator sectionSlot hole 10 (12 7sim4) 3 MS1Auxiliary hole 18 (15sim32) 25 HS6Peripheral hole 15 (33sim47) 21 HS10Nos 3ndash6 are large empty holes e detonator segments 1-2 7-8 and 9ndash14 are respectively MS1 MS9 and HS2 e detonator segments from 15 to 18 areHS3 19 to 22 are HS5 23 to 26 are HS6 27 to 29 are HS7 and 30 to 32 are HS8 e detonator segments of 33sim43 are HS9 while those of 44sim47 are HS10

4 12

13 17 25 381826

2061422

312

5

28 37161115

29

192423

31 36

453534

27

3344

43 30

42

41

47 40 39 46

7 8

10 9

21

32

Figure 6 Four-hole blasting scheme (the numbers in the figure represent the hole number)

(a)

Figure 7 Continued

Advances in Civil Engineering 7

5 Conclusion

In this paper it is theoretically analyzed that the existence ofempty holes can provide initial space for rock blasting and thenthe formation process of the cavity in the cutting area is sim-ulated by numerical simulation Finally the following conclu-sions are obtained by combining with the site blasting test

(1) Compared with two holes the arrangement of the fourholes optimizes the cutting area of the blasting and thesufficient empty hole space provides sufficient ex-pansion compensation space for rock blasting

(2) e existence of voids and explosive holes changesthe stress state of the gutter region and the complexdynamic effects are generated under the action ofcharge explosion e preferential fracture in thestress concentration area reflects the stress concen-tration of the pores

(3) For the blasting of the gutter area the four emptyholes play the role of energy constraint and guidanceto the charge of the inner layer and free surface to theexternal charge which jointly promote the formationof the cutting area

(4) emain causes of the formation of the tunnel cavityare the compressive stress and explosive gas of thedeep-hole cutting blasting and the tensile stress hasno obvious superiority in this process

In this study the influence of the cutting mode on theblasting effect of tunnel excavation gives that the four-holecutting mode is better than the two-hole cutting mode Inorder to prove the advantages of the scheme it should beapplied to the roadway with different cross-section sizes tofurther verify the advantages of its blasting effect

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e support from the National Natural Science Foundationof China (Grant no 51709257) and Science and TechnologyResearch Project of Hubei Education Department (Grant noD20171506) is sincerely appreciated

References

[1] J B Martino and N A Chandler ldquoExcavation-induceddamage studies at the underground research laboratoryrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 8 pp 1413ndash1426 2004

[2] M Ramulu A K Chakraborty and T G Sitharam ldquoDamageassessment of basaltic rock mass due to repeated blasting in arailway tunnelling projectmdasha case studyrdquo Tunnelling andUnderground Space Technology vol 24 no 2 pp 208ndash2212009

[3] J Yang W Lu Y Hu M Chen and P Yan ldquoNumericalsimulation of rock mass damage evolution during deep-buried tunnel excavation by drill and blastrdquo Rock Mechanicsand Rock Engineering vol 48 no 5 pp 2045ndash2059 2015

[4] L Zhang J-H Hu X-L Wang and L Zhao ldquoOptimizationof stope structural parameters based on mathews stabilitygraph probability modelrdquo Advances in Civil Engineeringvol 2018 Article ID 1754328 7 pages 2018

[5] K Soroush Y Mehdi and E Arash ldquoTrend analysis andcomparison of basic parameters for tunnel blast designmodelsrdquo International Journal of Mining Science and Tech-nology vol 25 no 4 pp 595ndash599 2015

[6] D Guo H Wang X Li et al ldquoNumerical analysis on ex-pansion chamber process of large hollow hole cut blasting inyixin coal minerdquo Blasting vol 34 no 2 pp 9ndash14 2017

[7] R Shan B Huang W Gao et al ldquoCase studies of newtechnology application of quasi-parallel cut blasting in rockroadway drivagerdquo Journal of RockMechanics and Engineeringvol 30 no 2 pp 224ndash232 2011

(b)

Figure 7 Comparison of on-site blasting effects (a) Original plan blasting effect (b) Four-hole blasting effect

8 Advances in Civil Engineering

[8] K Man X Liu J Wang and X Wang ldquoBlasting energyanalysis of the different cutting methodsrdquo Shock and Vi-bration vol 2018 Article ID 9419018 13 pages 2018

[9] G Yang L Jiang and R Yang ldquoInvestigation of cut blastingwith duplex wedge deep holesrdquo Journal of China University ofMining amp Technology vol 42 no 5 pp 755ndash760 2013

[10] X Ma M He J Sun H Wang X Liu and E Zhen ldquoNeuralnetwork of roof cutting blasting parameters based on mineswith different roof conditionsrdquo Energies vol 11 no 12p 3468 2018

[11] X Zhang ldquoGrey correlation analysis of influence factors ofblasting vibration with straight hollow hole cuttingrdquo Mu-nicipal Engineering Technology vol 36 no 3 pp 138ndash1402018

[12] H Wang Z Qi and Y Zhao ldquoNumerical analysis and ap-plication of large-diameter cavity parallel cut blasting stressfield in vertical shaftrdquo Chinese Journal of Rock Mechanics andEngineering vol 34 no S1 pp 3223ndash3229 2015

[13] J Zuo R Yang C Xiao et al ldquoModel test of empty hole cutblasting in coal mine rock drivagerdquo Journal of Mining Scienceand Technology vol 3 no 4 pp 335ndash341 2018

[14] D Lin and S Chen ldquoExperimental and theoretical study ofparallel hole cut blasting with cavityrdquo Rock and Soil Me-chanics vol 26 no 3 pp 479ndash483 2005

[15] D Lin Research on Size Effect of Empty Hole in HorizontalRoadway Cut Blasting amp Accumulating Characteristic ofSurrounding Rock Damage Caused by Frequently BlastingVibration Central South University Changsha China 2006

[16] X-F Pan and Y-F Mao ldquoe numerical simulation of shaftexcavation blasting cavity expansion process based onANSYSLS-DYNArdquo Coal Mine Blasting vol 108 no 4pp 19ndash24 2014

[17] J W Swegle and S W Attaway ldquoOn the feasibility of usingsmoothed particle hydrodynamics for underwater explosioncalculationsrdquo Computational Mechanics vol 17 no 3pp 151ndash168 1995

[18] S H Cho and K Kaneko ldquoInfluence of the applied pressurewaveform on the dynamic fracture processes in rockrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 5 pp 771ndash784 2004

[19] Y Liu Z Zhou J Li et al ldquoeoretical and experimentalstudy on empty hole effect in tunnel cut blastingrdquoMetal Minevol 368 no 2 pp 12ndash14 2007

[20] S Wang and Y Wang ldquoEmpty hole effect under three-borehole directional blasting loadrdquo Science and Technologyand Engineering vol 16 no 35 2016

[21] Q Chen H Li X Xiang et al ldquoResearch and application ofempty hole effect under blasting loadingrdquo Journal of ChinaCoal Society vol 41 no 11 pp 2749ndash2755 2016

[22] G Fu X Tan and F Gao ldquoStudy on rational blasting depth oftunnel passing under through airport runwayrdquo ChineseJournal of Underground Space and Engineering vol 8pp 1148ndash1152 2012

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

Table 2 Explosion parameters of the four-hole slotting scheme

Gun hole nameParameter

Number of holes Single hole charge (kg) Detonator sectionSlot hole 10 (12 7sim4) 3 MS1Auxiliary hole 18 (15sim32) 25 HS6Peripheral hole 15 (33sim47) 21 HS10Nos 3ndash6 are large empty holes e detonator segments 1-2 7-8 and 9ndash14 are respectively MS1 MS9 and HS2 e detonator segments from 15 to 18 areHS3 19 to 22 are HS5 23 to 26 are HS6 27 to 29 are HS7 and 30 to 32 are HS8 e detonator segments of 33sim43 are HS9 while those of 44sim47 are HS10

4 12

13 17 25 381826

2061422

312

5

28 37161115

29

192423

31 36

453534

27

3344

43 30

42

41

47 40 39 46

7 8

10 9

21

32

Figure 6 Four-hole blasting scheme (the numbers in the figure represent the hole number)

(a)

Figure 7 Continued

Advances in Civil Engineering 7

5 Conclusion

In this paper it is theoretically analyzed that the existence ofempty holes can provide initial space for rock blasting and thenthe formation process of the cavity in the cutting area is sim-ulated by numerical simulation Finally the following conclu-sions are obtained by combining with the site blasting test

(1) Compared with two holes the arrangement of the fourholes optimizes the cutting area of the blasting and thesufficient empty hole space provides sufficient ex-pansion compensation space for rock blasting

(2) e existence of voids and explosive holes changesthe stress state of the gutter region and the complexdynamic effects are generated under the action ofcharge explosion e preferential fracture in thestress concentration area reflects the stress concen-tration of the pores

(3) For the blasting of the gutter area the four emptyholes play the role of energy constraint and guidanceto the charge of the inner layer and free surface to theexternal charge which jointly promote the formationof the cutting area

(4) emain causes of the formation of the tunnel cavityare the compressive stress and explosive gas of thedeep-hole cutting blasting and the tensile stress hasno obvious superiority in this process

In this study the influence of the cutting mode on theblasting effect of tunnel excavation gives that the four-holecutting mode is better than the two-hole cutting mode Inorder to prove the advantages of the scheme it should beapplied to the roadway with different cross-section sizes tofurther verify the advantages of its blasting effect

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e support from the National Natural Science Foundationof China (Grant no 51709257) and Science and TechnologyResearch Project of Hubei Education Department (Grant noD20171506) is sincerely appreciated

References

[1] J B Martino and N A Chandler ldquoExcavation-induceddamage studies at the underground research laboratoryrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 8 pp 1413ndash1426 2004

[2] M Ramulu A K Chakraborty and T G Sitharam ldquoDamageassessment of basaltic rock mass due to repeated blasting in arailway tunnelling projectmdasha case studyrdquo Tunnelling andUnderground Space Technology vol 24 no 2 pp 208ndash2212009

[3] J Yang W Lu Y Hu M Chen and P Yan ldquoNumericalsimulation of rock mass damage evolution during deep-buried tunnel excavation by drill and blastrdquo Rock Mechanicsand Rock Engineering vol 48 no 5 pp 2045ndash2059 2015

[4] L Zhang J-H Hu X-L Wang and L Zhao ldquoOptimizationof stope structural parameters based on mathews stabilitygraph probability modelrdquo Advances in Civil Engineeringvol 2018 Article ID 1754328 7 pages 2018

[5] K Soroush Y Mehdi and E Arash ldquoTrend analysis andcomparison of basic parameters for tunnel blast designmodelsrdquo International Journal of Mining Science and Tech-nology vol 25 no 4 pp 595ndash599 2015

[6] D Guo H Wang X Li et al ldquoNumerical analysis on ex-pansion chamber process of large hollow hole cut blasting inyixin coal minerdquo Blasting vol 34 no 2 pp 9ndash14 2017

[7] R Shan B Huang W Gao et al ldquoCase studies of newtechnology application of quasi-parallel cut blasting in rockroadway drivagerdquo Journal of RockMechanics and Engineeringvol 30 no 2 pp 224ndash232 2011

(b)

Figure 7 Comparison of on-site blasting effects (a) Original plan blasting effect (b) Four-hole blasting effect

8 Advances in Civil Engineering

[8] K Man X Liu J Wang and X Wang ldquoBlasting energyanalysis of the different cutting methodsrdquo Shock and Vi-bration vol 2018 Article ID 9419018 13 pages 2018

[9] G Yang L Jiang and R Yang ldquoInvestigation of cut blastingwith duplex wedge deep holesrdquo Journal of China University ofMining amp Technology vol 42 no 5 pp 755ndash760 2013

[10] X Ma M He J Sun H Wang X Liu and E Zhen ldquoNeuralnetwork of roof cutting blasting parameters based on mineswith different roof conditionsrdquo Energies vol 11 no 12p 3468 2018

[11] X Zhang ldquoGrey correlation analysis of influence factors ofblasting vibration with straight hollow hole cuttingrdquo Mu-nicipal Engineering Technology vol 36 no 3 pp 138ndash1402018

[12] H Wang Z Qi and Y Zhao ldquoNumerical analysis and ap-plication of large-diameter cavity parallel cut blasting stressfield in vertical shaftrdquo Chinese Journal of Rock Mechanics andEngineering vol 34 no S1 pp 3223ndash3229 2015

[13] J Zuo R Yang C Xiao et al ldquoModel test of empty hole cutblasting in coal mine rock drivagerdquo Journal of Mining Scienceand Technology vol 3 no 4 pp 335ndash341 2018

[14] D Lin and S Chen ldquoExperimental and theoretical study ofparallel hole cut blasting with cavityrdquo Rock and Soil Me-chanics vol 26 no 3 pp 479ndash483 2005

[15] D Lin Research on Size Effect of Empty Hole in HorizontalRoadway Cut Blasting amp Accumulating Characteristic ofSurrounding Rock Damage Caused by Frequently BlastingVibration Central South University Changsha China 2006

[16] X-F Pan and Y-F Mao ldquoe numerical simulation of shaftexcavation blasting cavity expansion process based onANSYSLS-DYNArdquo Coal Mine Blasting vol 108 no 4pp 19ndash24 2014

[17] J W Swegle and S W Attaway ldquoOn the feasibility of usingsmoothed particle hydrodynamics for underwater explosioncalculationsrdquo Computational Mechanics vol 17 no 3pp 151ndash168 1995

[18] S H Cho and K Kaneko ldquoInfluence of the applied pressurewaveform on the dynamic fracture processes in rockrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 5 pp 771ndash784 2004

[19] Y Liu Z Zhou J Li et al ldquoeoretical and experimentalstudy on empty hole effect in tunnel cut blastingrdquoMetal Minevol 368 no 2 pp 12ndash14 2007

[20] S Wang and Y Wang ldquoEmpty hole effect under three-borehole directional blasting loadrdquo Science and Technologyand Engineering vol 16 no 35 2016

[21] Q Chen H Li X Xiang et al ldquoResearch and application ofempty hole effect under blasting loadingrdquo Journal of ChinaCoal Society vol 41 no 11 pp 2749ndash2755 2016

[22] G Fu X Tan and F Gao ldquoStudy on rational blasting depth oftunnel passing under through airport runwayrdquo ChineseJournal of Underground Space and Engineering vol 8pp 1148ndash1152 2012

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

5 Conclusion

In this paper it is theoretically analyzed that the existence ofempty holes can provide initial space for rock blasting and thenthe formation process of the cavity in the cutting area is sim-ulated by numerical simulation Finally the following conclu-sions are obtained by combining with the site blasting test

(1) Compared with two holes the arrangement of the fourholes optimizes the cutting area of the blasting and thesufficient empty hole space provides sufficient ex-pansion compensation space for rock blasting

(2) e existence of voids and explosive holes changesthe stress state of the gutter region and the complexdynamic effects are generated under the action ofcharge explosion e preferential fracture in thestress concentration area reflects the stress concen-tration of the pores

(3) For the blasting of the gutter area the four emptyholes play the role of energy constraint and guidanceto the charge of the inner layer and free surface to theexternal charge which jointly promote the formationof the cutting area

(4) emain causes of the formation of the tunnel cavityare the compressive stress and explosive gas of thedeep-hole cutting blasting and the tensile stress hasno obvious superiority in this process

In this study the influence of the cutting mode on theblasting effect of tunnel excavation gives that the four-holecutting mode is better than the two-hole cutting mode Inorder to prove the advantages of the scheme it should beapplied to the roadway with different cross-section sizes tofurther verify the advantages of its blasting effect

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e support from the National Natural Science Foundationof China (Grant no 51709257) and Science and TechnologyResearch Project of Hubei Education Department (Grant noD20171506) is sincerely appreciated

References

[1] J B Martino and N A Chandler ldquoExcavation-induceddamage studies at the underground research laboratoryrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 8 pp 1413ndash1426 2004

[2] M Ramulu A K Chakraborty and T G Sitharam ldquoDamageassessment of basaltic rock mass due to repeated blasting in arailway tunnelling projectmdasha case studyrdquo Tunnelling andUnderground Space Technology vol 24 no 2 pp 208ndash2212009

[3] J Yang W Lu Y Hu M Chen and P Yan ldquoNumericalsimulation of rock mass damage evolution during deep-buried tunnel excavation by drill and blastrdquo Rock Mechanicsand Rock Engineering vol 48 no 5 pp 2045ndash2059 2015

[4] L Zhang J-H Hu X-L Wang and L Zhao ldquoOptimizationof stope structural parameters based on mathews stabilitygraph probability modelrdquo Advances in Civil Engineeringvol 2018 Article ID 1754328 7 pages 2018

[5] K Soroush Y Mehdi and E Arash ldquoTrend analysis andcomparison of basic parameters for tunnel blast designmodelsrdquo International Journal of Mining Science and Tech-nology vol 25 no 4 pp 595ndash599 2015

[6] D Guo H Wang X Li et al ldquoNumerical analysis on ex-pansion chamber process of large hollow hole cut blasting inyixin coal minerdquo Blasting vol 34 no 2 pp 9ndash14 2017

[7] R Shan B Huang W Gao et al ldquoCase studies of newtechnology application of quasi-parallel cut blasting in rockroadway drivagerdquo Journal of RockMechanics and Engineeringvol 30 no 2 pp 224ndash232 2011

(b)

Figure 7 Comparison of on-site blasting effects (a) Original plan blasting effect (b) Four-hole blasting effect

8 Advances in Civil Engineering

[8] K Man X Liu J Wang and X Wang ldquoBlasting energyanalysis of the different cutting methodsrdquo Shock and Vi-bration vol 2018 Article ID 9419018 13 pages 2018

[9] G Yang L Jiang and R Yang ldquoInvestigation of cut blastingwith duplex wedge deep holesrdquo Journal of China University ofMining amp Technology vol 42 no 5 pp 755ndash760 2013

[10] X Ma M He J Sun H Wang X Liu and E Zhen ldquoNeuralnetwork of roof cutting blasting parameters based on mineswith different roof conditionsrdquo Energies vol 11 no 12p 3468 2018

[11] X Zhang ldquoGrey correlation analysis of influence factors ofblasting vibration with straight hollow hole cuttingrdquo Mu-nicipal Engineering Technology vol 36 no 3 pp 138ndash1402018

[12] H Wang Z Qi and Y Zhao ldquoNumerical analysis and ap-plication of large-diameter cavity parallel cut blasting stressfield in vertical shaftrdquo Chinese Journal of Rock Mechanics andEngineering vol 34 no S1 pp 3223ndash3229 2015

[13] J Zuo R Yang C Xiao et al ldquoModel test of empty hole cutblasting in coal mine rock drivagerdquo Journal of Mining Scienceand Technology vol 3 no 4 pp 335ndash341 2018

[14] D Lin and S Chen ldquoExperimental and theoretical study ofparallel hole cut blasting with cavityrdquo Rock and Soil Me-chanics vol 26 no 3 pp 479ndash483 2005

[15] D Lin Research on Size Effect of Empty Hole in HorizontalRoadway Cut Blasting amp Accumulating Characteristic ofSurrounding Rock Damage Caused by Frequently BlastingVibration Central South University Changsha China 2006

[16] X-F Pan and Y-F Mao ldquoe numerical simulation of shaftexcavation blasting cavity expansion process based onANSYSLS-DYNArdquo Coal Mine Blasting vol 108 no 4pp 19ndash24 2014

[17] J W Swegle and S W Attaway ldquoOn the feasibility of usingsmoothed particle hydrodynamics for underwater explosioncalculationsrdquo Computational Mechanics vol 17 no 3pp 151ndash168 1995

[18] S H Cho and K Kaneko ldquoInfluence of the applied pressurewaveform on the dynamic fracture processes in rockrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 5 pp 771ndash784 2004

[19] Y Liu Z Zhou J Li et al ldquoeoretical and experimentalstudy on empty hole effect in tunnel cut blastingrdquoMetal Minevol 368 no 2 pp 12ndash14 2007

[20] S Wang and Y Wang ldquoEmpty hole effect under three-borehole directional blasting loadrdquo Science and Technologyand Engineering vol 16 no 35 2016

[21] Q Chen H Li X Xiang et al ldquoResearch and application ofempty hole effect under blasting loadingrdquo Journal of ChinaCoal Society vol 41 no 11 pp 2749ndash2755 2016

[22] G Fu X Tan and F Gao ldquoStudy on rational blasting depth oftunnel passing under through airport runwayrdquo ChineseJournal of Underground Space and Engineering vol 8pp 1148ndash1152 2012

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

[8] K Man X Liu J Wang and X Wang ldquoBlasting energyanalysis of the different cutting methodsrdquo Shock and Vi-bration vol 2018 Article ID 9419018 13 pages 2018

[9] G Yang L Jiang and R Yang ldquoInvestigation of cut blastingwith duplex wedge deep holesrdquo Journal of China University ofMining amp Technology vol 42 no 5 pp 755ndash760 2013

[10] X Ma M He J Sun H Wang X Liu and E Zhen ldquoNeuralnetwork of roof cutting blasting parameters based on mineswith different roof conditionsrdquo Energies vol 11 no 12p 3468 2018

[11] X Zhang ldquoGrey correlation analysis of influence factors ofblasting vibration with straight hollow hole cuttingrdquo Mu-nicipal Engineering Technology vol 36 no 3 pp 138ndash1402018

[12] H Wang Z Qi and Y Zhao ldquoNumerical analysis and ap-plication of large-diameter cavity parallel cut blasting stressfield in vertical shaftrdquo Chinese Journal of Rock Mechanics andEngineering vol 34 no S1 pp 3223ndash3229 2015

[13] J Zuo R Yang C Xiao et al ldquoModel test of empty hole cutblasting in coal mine rock drivagerdquo Journal of Mining Scienceand Technology vol 3 no 4 pp 335ndash341 2018

[14] D Lin and S Chen ldquoExperimental and theoretical study ofparallel hole cut blasting with cavityrdquo Rock and Soil Me-chanics vol 26 no 3 pp 479ndash483 2005

[15] D Lin Research on Size Effect of Empty Hole in HorizontalRoadway Cut Blasting amp Accumulating Characteristic ofSurrounding Rock Damage Caused by Frequently BlastingVibration Central South University Changsha China 2006

[16] X-F Pan and Y-F Mao ldquoe numerical simulation of shaftexcavation blasting cavity expansion process based onANSYSLS-DYNArdquo Coal Mine Blasting vol 108 no 4pp 19ndash24 2014

[17] J W Swegle and S W Attaway ldquoOn the feasibility of usingsmoothed particle hydrodynamics for underwater explosioncalculationsrdquo Computational Mechanics vol 17 no 3pp 151ndash168 1995

[18] S H Cho and K Kaneko ldquoInfluence of the applied pressurewaveform on the dynamic fracture processes in rockrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 41 no 5 pp 771ndash784 2004

[19] Y Liu Z Zhou J Li et al ldquoeoretical and experimentalstudy on empty hole effect in tunnel cut blastingrdquoMetal Minevol 368 no 2 pp 12ndash14 2007

[20] S Wang and Y Wang ldquoEmpty hole effect under three-borehole directional blasting loadrdquo Science and Technologyand Engineering vol 16 no 35 2016

[21] Q Chen H Li X Xiang et al ldquoResearch and application ofempty hole effect under blasting loadingrdquo Journal of ChinaCoal Society vol 41 no 11 pp 2749ndash2755 2016

[22] G Fu X Tan and F Gao ldquoStudy on rational blasting depth oftunnel passing under through airport runwayrdquo ChineseJournal of Underground Space and Engineering vol 8pp 1148ndash1152 2012

Advances in Civil Engineering 9

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom