4mm4mm

Name：Yukio NAKATAAffiliation：Yamaguchi University

Effects of coral gravels on the mechanical behaviour  

Effects of crushing strength on mechanical behaviour

DEM simulation to understand the effect of crushing strength on mobilised bearing capacity

Research theme : GEO‐MECHANICS OF CRUSHABLE SOIL FROM MICRO TO MACROOBJECTIVE: Grain properties, grain crushing behaviour in granular material, compression and dilatancy behaviour depending on pressre, bearing capacities and slope stability  

40mm

20mm

4mm

1mm

0.2mm

6.66mm

1mm1mm

0.2mm0.2mm

6.66mm6.66mm

(45, 148)(45, 148) (44,130)(44,130) (46,141)(46,141)

0.7

0.9

1.1

1.3

1.5

1.7

1.9

2.1

0.01 0.1 1 10

Mean stress / 0

Voi

d ra

tio .

B.S.=4NB.S.=2NB.S.=1N

Yield point = 0.3

Critical pressure = 0.1

Critical state

Effects of fine grain content on slope stability due to rainfall

1200 1600 2000 2400 2800 32000

20

40

60

80

100

時間(s )

F.C.=5%

F.C.=25%

F.C.=20%

F.C.=10%崩壊領域割合

(%)

Percen

tage of collapsed

 area (%

)

Time (sec)

Granular mechanicsfor science, engineering,

and curiosity!Matsushima, T., Katagiri, J., Uesugi, K., Tsuchiyama, A., Nakano, T.: 3-D Shape Characterization and Image-based DEM simulation of Lunar soil simulant, FJS-1, Journal of Aerospace Engineering, ASCE, 22,1,pp.15-23, 2009.1.Katagiri, J., Matsushima, T., Yamada, Y.: Simple shear simulation of 3D irregularly-shaped particles by image-based DEM, Granular Matter, 12, 5, 491-497, 2010.Matsushima, T., Chang, C.S.: Quantitative evaluation of the effect of irregularly shaped particles in sheared granular assemblies, Granular Matter, 13:269–276, 2011Tsuchiyama, A., Uesugi, M., Matsushima, T., et al. : Three-Dimensional Structure of Hayabusa

Samples: Origin and Evolution of Itokawa

Regolith, Science 333, 1125, 2011 (DOI: 10.1126/science.1207807))Ueda, T., Matsushima, T., Yamada, Y: Effect of particle size ratio and volume fraction on shear strength of binary granular mixture, Granular Matter, 13:731–742, 2011Ueda, T., Matsushima, T., Yamada, Y.: Micro structures of granular materials with various grain size distributions, Powder Technology, 217, 533-539, 2012.02. http://www.kz.tsukuba.ac.jp/~tmatsu/

Name：Noriyuki YasufukuAffiliation：Kyushu University, Faculty of Engineering

Sand-steel interface friction over a wide shear deformation concerning to soil crushability/Objective: To make clear the Sand –steel Interaction properties at peak and residual  (large deformation) states and to reflect the results into a limit state design methodology of pile foundation

Development of high-performed pile foundation and its evaluation/Objective: To Develop a rational pile type with rotational and taper shaped functions to minimize the environmental impact  and its evaluation method as a limit state design.  

Pressing effect*Pressing effect*

Impr

oved

eff

ect o

f Im

prov

ed e

ffec

t of

bear

ing

capa

city

bear

ing

capa

city

Normalized settlement

Normalized settlement

*:Rate of soils pressed to the volume of pilePressing effect*Pressing effect*

Impr

oved

eff

ect o

f Im

prov

ed e

ffec

t of

bear

ing

capa

city

bear

ing

capa

city

Normalized settlement

Normalized settlement

*:Rate of soils pressed to the volume of pile

2

'cv

4'

2

'cv

4'

)}2sin1/()2sin1{(q 'cv

'cvpcalA

Fig. 1 (a) Concept of modified failure mechanism around the tapered pile tip in cavity expansion solution and (b) Geometry of calculation procedure to find ultimate end bearing capacity of tapered pile.

Fig.2 Ring shear apparatus used

do : 30 cmdin: 20 cmho : 4 cmSp: 0.15mm

Load cell

Load cell

0

0.2

0.4

0.6

0 200 400 600 800 1000

(a)

Horizontal displacement H(mm)

sample-1D50=0.17mm

Uc=1.5

B

n'=100kPaDr=50%

A

A

0

0.2

0.4

0.6

0 2 4 6 8 10H(mm)

(b)

:(Rmax=10m) :(Rmax=500m)

Fig.3 Typical t/sn‐H relationship from small to large deformation and definition of d 

0.00.51.01.52.02.53.0

0.05 0.10 0.15 0.20 0.25

Displacemen

t  mm

time s

Name：A. KonoAffiliation：Railway Technical Research Institute --- collaborative research with Tsukuba University

Mission1 : Finding out the most effective factor causing problems.Mission2 : Proposing some reducing methods for the factor.

Differential Settlement,Abraded Grains, Ballast Flow, and so on.

Various Patterns of Vehicle Loadings

0

50

100

150

200

250

0.05 0.10 0.15 0.20 0.25

Load

ing  kN

time s

0.00.51.01.52.02.53.0

0.05 0.10 0.15 0.20 0.25

Displacemen

t  mm

time s

Sleeper Displacement

with Impaction

ReplacingResilientRail Pad

Resilient Rail Pad

Ballasted Track Model with 19044 Ballast Grain Elements composed of Clumped-Spheres Model.

Sleeper Displacement

Name：Hidetaka SaomotoAffiliation：Active Fault and Earthquake Research Center, National Institute of Advanced Industrial Science and Technology

Pore fluid simulation based on LBM with GPU accelerationObjective: Construction of velocity model for ground water pollutio

DEM simulation of ground deformation caused by fault ruptureObjective: Prediction of surface rupture zone.

PDE (Partial Differential Equation) constrained optimization in the field of engineering Objective: Improvement of the drain topology for liquefaction countermeasures (in this case).

The black region indicates optimized drain shapeautomatically obtained from the FEM simulation combining with the optimizer based on the SQP algorithm.

Shear band formation due to faulting process (left: strike-slip, right: reverse dip-slip)

Name：Naotaka KIKKAWAAffiliation：National Institute of Occupational Safety and Health, Japan (JNIOSH)

MotivationReduce the fatalities due to rock fall eventsduring tunnel excavation.

BackgroundBlasting would force to rearrange the stresssurrounding a tunnel cutting face and then rockfalls due to the stress relaxation.

ObjectiveEvaluate the stress rearrangement by blasting.

ExperimentUsing a small size ignition charge, we blasted thebonded granular specimen which Toyoura sandwas bonded by a liquid agent.

SimulationUsing the three-dimensional Discrete ElementMethod (DEM), we simulated the experimentalblasting test.Blasting was only considered as the effect of

gas expansion, and then an element of sphericalrigid wall was installed in the centre of thespecimen. The spherical rigid wall was inflateduntil the maximum radius of 5mm and deflateduntil the initial radius of 1mm at a constant radiusspeed of 35mm/sec.

ResultsBoth experiment and simulation, the specimenswere broken horizontally. For the simulation, thetension force occurred surrounding the blasting,its force still remained inside the specimen afterblasting.

ConclusionThe tension force remained would stretch cracks

ExperimentDEM simulationSphere: yellow, Parallel-bond: blueForce(compression): black, Force(tension): red

0sec

0.047sec

0.064sec

Name：Takatoshi KiriyamaAffiliation：Shimizu Institute of Technology

Particle Based 3D Model Generation using 3D CAD SystemObjective: To reduce difficulties in the hand-made mesh generation and to avoid mesh-tangling during numerical simulation.

Particle Based Analysis

3D CAD

Model Generation

Penetration Simulation of Rigid Body Falling into GroundObjective : To evaluate the applicability of MPM.

Rigid BodyGround

t=0.0(sec) t=0.1(sec) t=0.2(sec) t=0.3(sec)

t=0.4(sec) t=0.5(sec) t=0.6(sec) t=0.7(sec)

Difference of Shear Band Formation Depending on Cap BoundaryObjective: Investigation of shear band formation process using particle based simulations.

a=10% a=2% a=5% a=15% a=50%

(b) Case2：Cap Free

(a) Case1：Cap Fixed Horizontally

a=2% a=5% a=10% a=15% a=50%

Cap

0

60

120

180

240

300

0 5 10 15

Dev

iato

ric S

tressσa

-σr(

kPa)

Axial Strain εa (%)

experimentsimulationm0=100(kPa)

m0=50(kPa)

m0=10(kPa)

Name：Daiki TAKANOAffiliation：Geotechnical Engineering Division, Port and Airport Research Institute

Seepage simulations in micro scale based on CT imagesObjective: Investigation of an effect of grain shape in seepage simulation using CT images.

Visualization and evaluation of mechanical behavior of granular materialsObjective: Quantitative evaluation of mechanical behavior of granular materials using X-ray tomography and image analysis

Dynamic centrifuge model test Objective: Investigation of an dynamic response using high speed camera and Digital Image correlation.

CT imageCT images of sand under triaxial compression

3D grain tracking:color correspond to magnitude of displacement of individual grains.

Extracted void space

Finite element meshFlow velocity field

Record ground behavior by high frame rate cameraTime history of response acceleration of ground

Displacement filed

Name：Tatsuo SakakibaraAffiliation：ITOCHU Techno-Solutions Corporation

Science & Engineering Systems Division

Fragmentation Analysis using DEM or SPHObjective: Establishment of modeling procedure for crack propagation of solid material by particle method.

Continues and discontinuous simulations

Multi scale simulations of composite materialObjective: Investigation of effect of micro structure such as glass fiber in resin.

Name：Shuji MoriguchiAffiliation：Tohoku University, International Research Institute of Disaster Science

Flow simulations of granular material using DEMObjective: Investigation of an effect of grain shape in flow simulation of granular material.

Particle-fluid coupled analysis using DEM and CFDObjective: Establishment of an numerical framework for direct simulation of soils.

A model test of rockfalls and it’s simulations using DEMObjective: Investigation of an effect of surface accuracy in rockfall simulations.

ExperimentSimulation

Name：Kenichi MAEDAAffiliation：Nagoya Institute of Technology, Advanced Disaster Prevention Engineering Center

duration of action

mag

nitu

de

of a

ctio

n fo

rce

longshort

MPa

Pa

Internal Erosion Project using DEM + CFD, SPHObjective: Modeling duality of discrete and continuum modeling and prediction of progressive depression in 3 phases.

TSUNAMI Project using DEM and/or SPH with three phase couplingObjective: Prediction of tsunami disaster and CAD for ductility and redundancy design in off-shore system.

Rockfall Project using DEMObjective: Impact propagation analysis and Proposal of counter-measure.

Heavy rainfall Project using SPH, DEM +CFDObjective: Seepage simulation of rainfall and rapid action of water to soil with three phases and reduction evaluation of flood damage.

Debris flow Project using DEM +CFDObjective: Changing grading in granular flow and evaluation of energy reduction.

Name：Keiko WatanabeAffiliation：Ritsumeikan University, Department of Mechanical Engineering

Observation of various phenomena using high-speed cameraObjective: Investigation of behavior of ejecta induced by high-speed penetration into granular material.

Development of vertical powder gun and gas gunObjective: High-speed impact experiments.

Objective: Investigation of behavior of projectile and sands during early penetration.

0 ms 5 ms

20 ms

10 ms

25 ms15 ms

-50 s

0 s

200 s

50 s

250 s150 s

100 s

300 s

Impact velocity: 350 m/sHigh-speed camera: MEMRECAMfx K3R (NAC)Frame rate: 1,000 fps (every 5 frames), Exposure: 50 s

Impact velocity: 495 m/sHigh-speed camera: ULTRA Cam HS-106E (NAC)Frame rate: 200,000 fps (every 10 frames), Exposure: 0.3s

Distribution of crashed d

Circumferential crashed sands

Massive crashed sands in front of projectile

Rear end of projectile

Crashed sand

10mm

ProjectileCone

10mm

Sands

Measurement of penetration velocity using magnet-coil gagesObjective: Establishment of accurate measuring method of penetration velocity into sand.

Penetration velocity measurement system Output signals of

coilImpact velocity: 510 m/s, Final penetration depth: 182.6 mm , t =0: Impact time to sands surface

Penetration depth vs. time

Penetration velocity vs. depth

Cell pressure 30 MPa Back Pressure 20 MPaAxial Load 200 kN Temperature control ‐35~50℃

Methane hydrate triaxial testing apparatusObjective: mechanical properties on methane

hydrate bearing soils

0

2

4

6

8

10

-

0 10 20 30 40 50Axial strain a(%)

De

via

tor

stre

ss q

(MP

a)

Ta

n=45% c'=3MPa

SMH=0%SMH=24.7%

SMH=56.0%

Ta

Methane hydrate plane strain triaxial testing apparatusObjective: mechanical properties and global and local deformation of methane hydrate bearing soils

Confining pressure 20 MPa Back Pressure 20 MPaAxial Load 200 kN Temperature control 0~30±1℃

0255075100

(%)a=0% a=2% a=4% a=6% a=8% a=10%

MH bearing sandSMH=48.0%

Stress and strain relationship forMH bearing sand

Global stress and strain relationship and local shear strain by plane strain test

Name：Masayuki HyodoAffiliation：Yamaguchi University, Dept. of Civil and Environmental Engineering

0

2

4

6

8

10

12

5

0

-5

0 1 2 3 4 5 6 7 8 9 10

SMH= 48.0%

prin

cipa

l str

ess

diff

eren

ce

' 1

- ' 3

(MP

a)

Vol

umet

ric

stra

in

v(%

)

Axial strain a(%)

Toyoura sand c=3.0MPa

SMH= 0.0%

Camera LE

D

Photographing of specimen

SEM images for MH bearing sand

Name：Masuhiro BeppuAffiliation：National Defense Academy, Department of Civil and Environmental Engineering

Flow simulations of hydraulic bore in natural dam using MPSObjective: Evaluation of impulsive force due to hydraulic bore causedby collapse of sediment into natural dam.

Numerical analysis of Debris flow using MPS and DEMObjective: Evaluation of impulsive load due to impact of debris flow.

Experiment Simulation

Excavation analysis of ground using SPH methodObjective: Prediction of entire deformation process of ground from small strain region to large deformation region.

Simulation of shear test of soils using SPH methodObjective: Establishment of a numerical framework for meshfree method with an elasto-plastic constitutive model considering soil skeleton structure.

Slope stability and deformation analysis using SPH methodObjective: Estimation of stability and deformation of slope simultaneously

Name：Hideto NonoyamaAffiliation：Nagoya University, Department of Civil EngineeringE-mail：nonoyama@civil.nagoya-u.ac.jp

0

50

100

150

200

250

300

0 50 100 150 200 250 300

Dev

iato

r stre

ss q

[kPa

]

Mean stress p [kPa]

0

0.2

0.4

0.6

0.8

1

1.2

0 2 4 6 8 10

R

Shear strain s [%]

0

0.2

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0.8

1

1.2

0 2 4 6 8 10

R*

Shear strain s [%]

0

50

100

150

200

250

300

0 2 4 6 8 10

Case1(theory)Case2(theory)

Case1(SPH)Case2(SPH)

Dev

iato

r stre

ss q

[kPa

]

Shear strain s [%]

0

0.2

0.4

0.6

0.8

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1.2

0 2 4 6 8 10Shear strain

s [%]

R

0

50

100

150

200

250

300

0 2 4 6 8 10

Case3(theory)Case4(theory)Case5(theory)Case6(theory)

Case3(SPH)Case4(SPH)Case5(SPH)Case6(SPH)

Shear strain s [%]

Dev

iato

r stre

ss q

[kPa

]

0

50

100

150

200

250

300

0 50 100 150 200 250 300

Dev

iato

r stre

ss q

[kPa

]

Mean stress p [kPa]

0

0.2

0.4

0.6

0.8

1

1.2

0 2 4 6 8 10Shear strain

s [%]

R*

「Typical clay」 「Typical sand」

Real-scale slope excavation experiment

Simulation