advance foundation engineering design principles

7/31/2019 Advance Foundation Engineering Design Principles

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ADVANCE FOUNDATIONADVANCE FOUNDATIONENGINEERINGENGINEERING

ASSOC. PROF. Ir. DR. RAMLIASSOC. PROF. Ir. DR. RAMLI NAZIRNAZIR


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SUCCESSFUL FOUNDATIONENGINEERING FAILURE


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Normally there are 3 stages of design i.eNormally there are 3 stages of design i.e

1.1. PRE DESIGN STAGEPRE DESIGN STAGE

2.2. CONSTRUCTION STAGECONSTRUCTION STAGE

3.3. POST DESIGN STAGEPOST DESIGN STAGE

Accurate and reliable SI data is vital.Accurate and reliable SI data is vital.

Type of foundation use for the structure is based from theType of foundation use for the structure is based from the

a ove.a ove.An overall aspect and anticipation during construction has to beAn overall aspect and anticipation during construction has to be

..

During this stage, loading, foundation arrangement and location,During this stage, loading, foundation arrangement and location,..

Anticipation of the problem in foundation construction workAnticipation of the problem in foundation construction workshould be reco nised and overcomin the roblem should beshould be reco nised and overcomin the roblem should be

readily available.readily available.


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Which one to use???Which one to use???

TOTAL STRESS ANALYSISTOTAL STRESS ANALYSIS

OrOr

EFFECTIVE STRESS ANALYSISEFFECTIVE STRESS ANALYSIS

This type of analysis uses the undrained shear strength of theThis type of analysis uses the undrained shear strength of thecohesive soil and also known as short term analysis.cohesive soil and also known as short term analysis.

e un ra ne s ear strengt , ce un ra ne s ear strengt , cuu can e o ta ne rom e succan e o ta ne rom e sucas vane shear and laboratory such as unconfined compressionas vane shear and laboratory such as unconfined compression..

depth then cdepth then cuu = c and= c and =0=0oo. The use of unconsolidated. The use of unconsolidated

undrained triaxial compression test is also applicable providedundrained triaxial compression test is also applicable providedthat it is saturated plastic soil.that it is saturated plastic soil.

The groundwater does not have an effect in the use of totalThe groundwater does not have an effect in the use of totalstress parameters.stress parameters.


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Firm to stiff saturated lastic soils are intermediate conditions.Firm to stiff saturated lastic soils are intermediate conditions.

The OCR and the tendency of the saturated plastics soiltoThe OCR and the tendency of the saturated plastics soiltoconsolidate will determine whether the TSA or ESA provides theconsolidate will determine whether the TSA or ESA provides thelower bearing capacity.lower bearing capacity.

SITE INVESTIGATIONSITE INVESTIGATION


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AA processprocess ofof sitesite explorationexploration consistingconsisting ofof boring,boring, samplingsampling andand

testingtesting soso asas toto obtainobtain geotechnicalgeotechnical informationinformation forfor aa safe,safe,..

conditionsconditions..

InIn otherother wordswords thethe mainmain purposepurpose ofof sitesite investigationinvestigation isis toto

determinedetermine withinwithin racticalractical limitslimits thethe de thde th thicknessthickness extentextent andandcompositionscompositions ofof eacheach subsoilsubsoil stratum,stratum, thethe depthdepth andand typetype ofof rock,rock,thethe depthdepth andand compositioncomposition ofof groundground water,water, thethe strength,strength,compressibilitycompressibility andand hydraulichydraulic charactristicscharactristics ofof soilsoil stratastrata asasrequiredrequired byby geotechnicalgeotechnical engineersengineers..

To study the general suitability of the site for an engineeringTo study the general suitability of the site for an engineeringproject. (FEED Program)project. (FEED Program)-- FRONTIER EVALUATIONFRONTIER EVALUATION

..

, ., .

o e erm ne e oss e cu es a may e encoun ereo e erm ne e oss e cu es a may e encoun ereby a specific construction method.by a specific construction method.

To study the suitability of construction material (soil or rock).To study the suitability of construction material (soil or rock).


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..

This is a part of geotechnical processes.This is a part of geotechnical processes.

Lack of geotechnical processes will lead to a:Lack of geotechnical processes will lead to a:--

Failures where many case histories areFailures where many case histories areavailable.available.

Si nificant dela and increase in constructionSi nificant dela and increase in constructioncosts when the design has to be revised orcosts when the design has to be revised or

ammended.ammended.

project thus it only comprises from only 0.1% to 5% of theproject thus it only comprises from only 0.1% to 5% of thepro ect cost.pro ect cost.

YOU HAVE TO PAY FOR THE S.IYOU HAVE TO PAY FOR THE S.I

WHETHER YOU LIKE IT OR NOT!!WHETHER YOU LIKE IT OR NOT!!


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FACTORS INFLUENCING SELECTION OFFACTORS INFLUENCING SELECTION OFSI METHODSSI METHODS

Geological nature of site.Geological nature of site.

Topographical Nature of the siteTopographical Nature of the site

Type of information requiredType of information required

Financial Constraint and Time Restriction.Financial Constraint and Time Restriction.

WORK PROCEDURE FOR SITEWORK PROCEDURE FOR SITEINVESTIGATIONINVESTIGATION

Desk study to collect all the relevant data and informationDesk study to collect all the relevant data and information

ReconnaissanceReconnaissance

Plannin ro ram after reviewin the above.Plannin ro ram after reviewin the above.

Ground exploration: Boring, sampling and testing.Ground exploration: Boring, sampling and testing.

Laboratory testingLaboratory testing

repara on o reporrepara on o repor

DesignDesign

Review during construction and monitoring.Review during construction and monitoring.


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Location Plan : Preferably in a scale of 1:60000Location Plan : Preferably in a scale of 1:60000

Site PlanSite Plan

Other details such as loading condition, preliminary SI reports ifOther details such as loading condition, preliminary SI reports ifany should be included.any should be included.

PLANNING OF SITE INVESTIGATIONPLANNING OF SITE INVESTIGATIONWORKSWORKS

Surface InvestigationsSurface Investigations

SiteSite inspectioninspection toto assessassess generalgeneral sitesite conditionconditionifif therethere isis anyany anticipatedanticipated problemsproblems thatthat mightmightarisearise duringduring thethe constructionconstruction laterlater onon..

UsuallUsuall thethe en ineeren ineer isis re uiredre uired toto ins ectins ect thethesitesite toto appreciateappreciate actualactual sitesite andand groundgroundroblemsroblems withwith articulararticular referencereference toto terrainterrain

vegetation,vegetation, swamps,swamps, waterwater runrun off,off,strati ra hicalstrati ra hical formationsformations wherewhere thethe areareexposedexposed..


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PLANNING SCOPE OF SITEPLANNING SCOPE OF SITEINVESTIGATIONINVESTIGATION

Select methods of SI base on rinci le and uidelines sti ulatedSelect methods of SI base on rinci le and uidelines sti ulatedin BS 5390.in BS 5390.

Important considerations are : terrain features and accessibility,Important considerations are : terrain features and accessibility,geological conditions, types of sample and test required.geological conditions, types of sample and test required.

Estimate cost and time required.Estimate cost and time required.

Determine the number, depth and spacing of boreholes or otherDetermine the number, depth and spacing of boreholes or otherfield tests including the location of test, procedures etc.field tests including the location of test, procedures etc.

Determine frequency and types of insitu testing and sampling inDetermine frequency and types of insitu testing and sampling ineach borehole.each borehole.

Determine extent of supervision on testing and boring.Determine extent of supervision on testing and boring.

Prepare list of special precautions for the site investigationPrepare list of special precautions for the site investigationsuperv sor at s te, any.superv sor at s te, any.

Prepare scheme of laboratory testing after analysis of borelogs.Prepare scheme of laboratory testing after analysis of borelogs.

ROLE OF SI IN GEOTECHNICAL ENGINEERING DESIGNROLE OF SI IN GEOTECHNICAL ENGINEERING DESIGN

ENGINEERING PROPERTIES

SI SOILPROPERTIES

BASIC & INDEX PROPERTIES

MASS PROPERTIES

TYPICAL & GENERALISEDSUBSOIL PROFILE &

INTERPRETATION

JUDGEMENT

CHARACTERIZATION

GEOLOGICAL FORMATIONS,MAN MADE FILL etc..

ENGINEERING GEOLOGYMODELLING

GROUND

SOIL & ROCK MECHANICS

EFFECTIVE STRESS THEORY

SEEPAGE THEORY

CODE OF PRACTICES:- FOUNDATION BS 8004ANCHORS BS8081

PREDICTION

BEHAVIOUR

STRESS DISTRIBUTION

LATERAL PRESSURE

BEARING CAPACITY

COMPRESSIBILITY

REINFORCED FILLS BS8006GEOGUIDES

DEFORMATION

DISPLACEMENT

ENGINEERING INSTRUMENTATION FOR

STABILITY

PERFORMANCE EARTH PRESSURE DISPLACEMENT(SURFACE & SUBSURFACE INTERNAL STRESSES


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JKR PROBEJKR PROBE

HAND AUGERING (HA)HAND AUGERING (HA)MOTORISED HAND BORING (MHB)MOTORISED HAND BORING (MHB)

DEEP BORING (DB)DEEP BORING (DB)

TRIAL PITS AND PLATE BEARING TESTTRIAL PITS AND PLATE BEARING TEST

DEEP SOUNDING (DS)DEEP SOUNDING (DS)

INSITU VANE SHEAR TEST (IVST)INSITU VANE SHEAR TEST (IVST)

STANDARD PENETRATION TEST (SPT)STANDARD PENETRATION TEST (SPT)PRESSUREMETER TESTPRESSUREMETER TEST

GROUND WATER INVESTIGATIONGROUND WATER INVESTIGATION

ROCK CORINGROCK CORING

Simple and cheap dynamic penetrometer test used to check theSimple and cheap dynamic penetrometer test used to check theconsistency of subsoil.consistency of subsoil.

eve op y n an a ways m sta en w t ac ntoseve op y n an a ways m sta en w t ac ntosProbe.Probe.

at a height of 280mm through free fall.at a height of 280mm through free fall.

penetration.penetration.

Maximum enetration is about 12m or 400 blows 300mmMaximum enetration is about 12m or 400 blows 300mm

whichever arrives first.whichever arrives first.The robe is unable to enetrate into medium stren th soil andThe robe is unable to enetrate into medium stren th soil andgravelly ground.gravelly ground.


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Simple boring by hand with periodic removal of soil samples.Simple boring by hand with periodic removal of soil samples.

Normally no casing is used.Normally no casing is used.Usually used in soft to stiff cohesive soils or sandy silty soilUsually used in soft to stiff cohesive soils or sandy silty soilabove water table.above water table.

ept s m te a out m an t e ameter o t e ore o e sept s m te a out m an t e ameter o t e ore o e sabout 100mm.about 100mm.

s very use u o ge e so samp e or so c ass ca ons very use u o ge e so samp e or so c ass ca ontests and ground water observation.tests and ground water observation.

,,collapse and boiling may be noted even for a short exposurecollapse and boiling may be noted even for a short exposure(indicating shallow foundation is not practical)(indicating shallow foundation is not practical)

Commonly called wash boring consists of tripod with block andCommonly called wash boring consists of tripod with block andtackle or motor driven winch.tackle or motor driven winch.

e ore o e s a vance y c opp ng w e tw st ng ro s ane ore o e s a vance y c opp ng w e tw st ng ro s anwashing with pumpwashing with pump--circulated water.circulated water.

,,those containing big boulders.those containing big boulders.

especially when deeper than 10m.especially when deeper than 10m.

Ado ted easil at locations where access is difficult.Ado ted easil at locations where access is difficult.

Normally casing is used and depth of boring is about 20m.Normally casing is used and depth of boring is about 20m.


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DEEP BORINGDEEP BORING

Also refer as rotary drilling.Also refer as rotary drilling.

Basic component including drilling machine, drilling rods, casing,Basic component including drilling machine, drilling rods, casing,bits and sampling tools.bits and sampling tools.

Basic field test sets are SPT sets, vane shear set, MenardBasic field test sets are SPT sets, vane shear set, Menard

pressuremeter, etc.pressuremeter, etc.Borehole is advance by power rotation of drilling bit andBorehole is advance by power rotation of drilling bit andremova o cutt ngs y t e c rcu at ng water.remova o cutt ngs y t e c rcu at ng water.

Drilled rod are presented by hydraulic pressure.Drilled rod are presented by hydraulic pressure.

enever roc an ou ers are encountere , su ta e amonenever roc an ou ers are encountere , su ta e amonbits or tungsten carbide bits are to be used.bits or tungsten carbide bits are to be used.

as ng nee e o e use an c ang ng n s ra a are n ca e y as ng nee e o e use an c ang ng n s ra a are n ca e y

changing in the rate of advancing of borehole action of drillingchanging in the rate of advancing of borehole action of drillingrods and visual examination of cuttin s in drillin fluid.rods and visual examination of cuttin s in drillin fluid.

This is the most expensive soil investigation method but yet aThis is the most expensive soil investigation method but yet acomprehensive type.comprehensive type.


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ROTARY WASH BORING

Depth is usually about 5m and the side of open cuts need to beDepth is usually about 5m and the side of open cuts need to bebraced.braced.

or easy v sua exam nat on o so strata n t e r naturaor easy v sua exam nat on o so strata n t e r naturaconditions.conditions.

and design pressure is high.and design pressure is high.

rocks above water table or cohesive soils containing considerablerocks above water table or cohesive soils containing considerableamount of boulders or cobbles.amount of boulders or cobbles.

It is also used to locate buried pipes and services.It is also used to locate buried pipes and services.


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Vertical plate bearing is usually carried out in trial pit toVertical plate bearing is usually carried out in trial pit todetermine the shear strength and deformation characteristics ofdetermine the shear strength and deformation characteristics ofsoil/rock beneath the loaded plate.soil/rock beneath the loaded plate.

Useful in weathered rock, highly fractured rock, hardcore fill orUseful in weathered rock, highly fractured rock, hardcore fill or

where other test procedure are difficult or impossible to apply.where other test procedure are difficult or impossible to apply.

Square and circular plate is used to load in order to obtain theSquare and circular plate is used to load in order to obtain theloadload--settlement curve.settlement curve.

influence is limited by virtue of limited plate size.influence is limited by virtue of limited plate size.

In absence of additional penetrometer tests like SPT and JKRIn absence of additional penetrometer tests like SPT and JKRProbes, the test can be misleading.Probes, the test can be misleading.

DEEP SOUNDINGDEEP SOUNDING

Refers to static dutch cone penetrometer.Refers to static dutch cone penetrometer.oo

the end area of 10cmthe end area of 10cm22..

Com arativel a fast economical and sim le method and verCom arativel a fast economical and sim le method and ver

useful in coastal alluvial and thick deposits of weak to moderatelyuseful in coastal alluvial and thick deposits of weak to moderatelystrong soils.strong soils.

Deep soundaing cannot penetrate very dense soils with gravel orDeep soundaing cannot penetrate very dense soils with gravel orsoft rocks.soft rocks.

It does not reveal soil types but by Schmertmann method it canIt does not reveal soil types but by Schmertmann method it cancorrelate the type of soils.correlate the type of soils.

In permeable soils, deep sounding results give drained conditionIn permeable soils, deep sounding results give drained conditionstrength while in clays, it measures undrained strength of thestrength while in clays, it measures undrained strength of the

..


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Cone ResistanceCone Resistance

CCkdkd(kg/cm(kg/cm22))

Relative DensityRelative Density

DDrr (%)(%)

Angle of InternalAngle of InternalFriction,Friction,

< 20< 20 < 20< 20 2525 -- 3030

2020 -- 4040 2020 -- 4040 3030 -- 3535

4040 -- 120120 4040 6060 3535 -- 4040

120120 -- 200200 6060 -- 8080 4040 -- 4545

--

== >=>=ss

ffss = C= Ckdkd/150/150 if Cif Ckdkd


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Used to determine the undrained cohesion of clay in fieldUsed to determine the undrained cohesion of clay in field

conditions which are generally difficult to simulate in the lab.conditions which are generally difficult to simulate in the lab.as ca y cons sts o t e our a e vane t at w penetrate ntoas ca y cons sts o t e our a e vane t at w penetrate nto

the undisturbed soil and rotated at a constant rate between 6the undisturbed soil and rotated at a constant rate between 6oo totooo ..

The results are reliable for saturated clayey soil without gravel orThe results are reliable for saturated clayey soil without gravel orcoarse sands.coarse sands.

For very soft to stiff clay (cFor very soft to stiff clay (cuu < 50kPa) the blade size should be< 50kPa) the blade size should be

75mm wide by 150mm long.75mm wide by 150mm long.For stronger soil (cFor stronger soil (cuu between 50 and 100 kPa) the blade sizebetween 50 and 100 kPa) the blade sizeshould be 50mm to 100mm long.should be 50mm to 100mm long.

This a dynamic field test usually carried out in boreholes.This a dynamic field test usually carried out in boreholes.

Test consists of driving a standard split barrel sampler 50.8mmTest consists of driving a standard split barrel sampler 50.8mmin diameter.in diameter.

The SPT is read from a 65kg drop hammer fall at a verticalThe SPT is read from a 65kg drop hammer fall at a verticale g o cm.e g o cm.

e samp er s r ven to a tota o cm nto t e so an t ee samp er s r ven to a tota o cm nto t e so an t e

number of blows recorded for the last 30cm of penetrationnumber of blows recorded for the last 30cm of penetration--,,


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,,


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STANDARD PENETRATION TEST VALUESTANDARD PENETRATION TEST VALUEFOR DESIGNFOR DESIGN

eve ope n an current y t e most popu ar met o an econom ca means to o ta neve ope n an current y t e most popu ar met o an econom ca means to o ta nsubsurface information.subsurface information.

Currently 85%Currently 85% -- 90% of usage in conventional foundation design.90% of usage in conventional foundation design.est cons st o :est cons st o :--

Driving the split barrel sample at a distance of 460mm into the soil at the bottom of boring.Driving the split barrel sample at a distance of 460mm into the soil at the bottom of boring.

Counting the number of blows to drive sample at last two 150mm distances to obtain NCounting the number of blows to drive sample at last two 150mm distances to obtain Nvaluevalue

Using 63.5kg driving mass falling free from a height of 760mm.Using 63.5kg driving mass falling free from a height of 760mm.

The boring log shows refusal and the test is halted if:The boring log shows refusal and the test is halted if:--

50 blows are required for any 150mm increment50 blows are required for any 150mm increment

100 blows are obtained to drive the required 300mm100 blows are obtained to drive the required 300mm

10 successive blows produce no advance.10 successive blows produce no advance.

When full test depth cannot be obtained, boring log will show aWhen full test depth cannot be obtained, boring log will show a

a penetration of 100mm.a penetration of 100mm.

The blow count is directl related to the drivin ener :The blow count is directl related to the drivin ener :--

W1

mv2

1E

2

2

gh2v

vg2

--

Wh

gh2g

W

2

1E

W= weight of mass or hammer

H = height of fall

For standard test:For standard test:--

E = 63.5 x 9.81 x 0.762E = 63.5 x 9.81 x 0.762


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ovac an a omone oun t at t e actua energy mpact to t e samp er range a out toovac an a omone oun t at t e actua energy mpact to t e samp er range a out to80% while Riggs (1983) obtained energy input from 70% to 100%80% while Riggs (1983) obtained energy input from 70% to 100%

The discrepancies arises from:The discrepancies arises from:--

Driving hammer configurationDriving hammer configuration

Usage of liner inside the barrelUsage of liner inside the barrel

Overburden ressureOverburden ressure

Length of drill rodLength of drill rod

Therefore SPT can be standardised to some energy ratio ETherefore SPT can be standardised to some energy ratio Err such that:such that:--

EErr= (Actual hammer energy to sampler (E= (Actual hammer energy to sampler (Eaa)/ Input Energy (E)) x 100)/ Input Energy (E)) x 100

Energy input of 70% is normally use since observation is close toEnergy input of 70% is normally use since observation is close tothe actual energy ratio (the actual energy ratio (EErr))

ere ore t e stan ar ow countere ore t e stan ar ow count 7070 s measure rom ass measure rom asfollows:follows:

NN7070 = C= CNN x N xx N x xx xx xx

WhereWhere ii = adjustment factor from table= adjustment factor from table

7070 = uste= uste

CCNN = Adjustment for effective overburden pressure= Adjustment for effective overburden pressure

'p

76.95C

o

N

po in kPa


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Note that largerNote that larger EErr decrease the blow count nearly linearlydecrease the blow count nearly linearly

i.ei.e EEr45r45 gives N=20gives N=20

EEr90r90 gives N = 10gives N = 10

==r70r70

Energy ratio x blow count should be constant thus :Energy ratio x blow count should be constant thus :-- 1r

22r11r

E

xNExNE

Say ESay Er1r1 = 70 thus gives N= 70 thus gives N22 = (70/E= (70/Er2r2)xN)xN11

1

2rE

Say NSay N22 for Efor Er45r45 = 20 = E= 20 = Er2r2We obtain NWe obtain N11 = 13= 13

If we convert NIf we convert N7070 to Nto N6060 than N2 = N60 = (70/60)x13 = 15than N2 = N60 = (70/60)x13 = 15

Using the equation we can readily convert any energy ratio to any other base.Using the equation we can readily convert any energy ratio to any other base.


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It can be used in correlation for unit weightIt can be used in correlation for unit weight relative density,relative density,

DDrr, angle of internal friction angle, angle of internal friction angle , undrained compressive, undrained compressive,, uu,, -- ..

Angle of internal friction:Angle of internal friction:--20N5.4 70

Relative DensityRelative Density o2r

70

'p288.032

D

'N

ase rom eyer o :ase rom eyer o :

where pwhere poo is in kPais in kPaoOCR

70 'BCA'Nor empton suggest t e o ow ng a ustment asor empton suggest t e o ow ng a ustment asbeen made:been made:--

2

rD

Where A range between 15 to 54Where A range between 15 to 54

. .. .

AndAndonc

OCR

'pC

oOCR'p

For CFor COCROCR=1 it relates to normally consolidated clay=1 it relates to normally consolidated clayrD

o15

o28

Thus Meyerhof estimate:Thus Meyerhof estimate:--

A correlation for N versus qA correlation for N versus quu in general form of:in general form of:--

qquu = kN= kN

ere ten to e s te epen ant.ere ten to e s te epen ant.

However k = 12 has been used i.e for NHowever k = 12 has been used i.e for N7070 = 10, q= 10, quu = 120kPa= 120kPa


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--


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Relationship between Angle of Internal Friction and N-Value(Sandy Soil)

SPT (Standard Penetration Test)

Hammer TypeHammer TypeSPTSPT

N-SPT = Total No. o Blows or s oon sam ler to enetrate at a

c (t/m2) = 2/3 N

depth of 30cm


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Relationship between Cohesion and N-Value (Cohesive soil)


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Dented orDented or detorneddetorned driving shoesdriving shoes

Driving Sampler above base of casingDriving Sampler above base of casing

Inadequate cleaning of boreholeInadequate cleaning of boreholeInadequate supervision or observationInadequate supervision or observation Carelessness in blow countingCarelessness in blow counting

Penetration depth not marked clearlyPenetration depth not marked clearly

Sam ler fre uentl im eded b coarse ravel or cobbles causin aSam ler fre uentl im eded b coarse ravel or cobbles causin asudden increase in blow counts. Observe rate of penetration andsudden increase in blow counts. Observe rate of penetration andsample recovered. Indicate this in bore log.sample recovered. Indicate this in bore log.

Alwa s kee boreholes full of water orAlwa s kee boreholes full of water or bentonitebentonite solution tosolution to minimiseminimisequick or boiling condition especially in sandy strata at great depth.quick or boiling condition especially in sandy strata at great depth.

Ensure hammer does not strike dolly eccentrically.Ensure hammer does not strike dolly eccentrically.

Use standard hammer with guide rod.Use standard hammer with guide rod.


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--

Current practise is to use an average N but in the zone ofCurrent practise is to use an average N but in the zone ofmajoring stress.majoring stress.

prea oun at onprea oun at on t e zone o nterest s rom a out tot e zone o nterest s rom a out to2B below the base of footing.2B below the base of footing.iz.N

i

av

z

For pile foundations, there may be merit in the simple average ofFor pile foundations, there may be merit in the simple average of..

It may be better to subdivide the thick stratum into several strataIt may be better to subdivide the thick stratum into several strata

Average corrected NAverage corrected N7070 can be computed and then average.can be computed and then average.


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Pile LocationPile Location Skin Resistance (kN)Skin Resistance (kN) End Bearing (kN)End Bearing (kN)

SandSand 3 N3 NavavAAss 400 N400 NbbAAbb

SiltSilt 2.5 N2.5 NavavAAss 300 N300 NbbAAbb

avav ss

Using MenardUsing Menard PressuremeterPressuremeter test to carry out in a borehole bytest to carry out in a borehole bya y ng ressure.a y ng ressure.

ForFor undrainedundrained condition, the pressure is maintained for a minutecondition, the pressure is maintained for a minute..

The probe pressure, in applied step, is increasedThe probe pressure, in applied step, is increased untilluntill limitlimitressure Pressure P ..

--

== ==11 oo uu,,

ccuu = (P= (P11 PPoo)/10 + 2.5 (kg/cm)/10 + 2.5 (kg/cm22))

--

PP11 = P= PooNN22where N = tanwhere N = tan22(45 +(45 + /2)/2)


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GROUND WATER INVESTIGATIONGROUND WATER INVESTIGATION

Parameters of importance in groundwater investigation are:Parameters of importance in groundwater investigation are: Existence of water table; normal perched or artisan.Existence of water table; normal perched or artisan.

Exact GWT and lower limit ofExact GWT and lower limit of erhederhed round waterround water

Thickness of strata and theThickness of strata and the piezometricpiezometric level of artisan groundwater.level of artisan groundwater.

Variation of these characteristics over the site and with timeVariation of these characteristics over the site and with time ..

Precaution taken while collecting water samples:Precaution taken while collecting water samples:

..

If possible collect the water before addition of water to borehole.If possible collect the water before addition of water to borehole.

Make sure the subsoil water is not contaminated by rain water or surface water.Make sure the subsoil water is not contaminated by rain water or surface water.

,,and then allowing to riseand then allowing to rise titi its original position and collect the water sample.its original position and collect the water sample.

Water sample shall be stored in airtight and clean container.Water sample shall be stored in airtight and clean container.

..

To determine the soundness of rock.To determine the soundness of rock. SoundSound rockrock :: RockRock whichwhich ringring whenwhen struckstruck withwith aa pickpick oror barbar.. DoesDoes notnot integrateintegrate

afterafter exposureexposure toto airair oror water,water, breaksbreaks withwith aa sharp,sharp, freshfresh fracture,fracture, inin whichwhich

crackscracks areare unweatheredunweathered andand lessless thanthan 33mmmm widewide andand generallygenerally notnot closercloser thanthan11mm apartapart.. CoreCore recoveryrecovery isis normallynormally 8585%%..

MediumMedium rockrock :: CharacteristicCharacteristic asas forfor soundsound rockrock butbut thethe crackscracks maybemaybe 66mmmm widewideandand slightlyslightly weathered,weathered, generallygenerally nono closercloser thanthan 6060cmcm.. CoreCore recoveryrecovery isis 5050%% orormoremore..

IntermediateIntermediate rockrock :: GiveGive dulldull soundsound whenwhen hithit byby pickpick oror barbar.. DoesDoes notnot integrateintegrateafterafter exposureexposure toto airair oror waterwater.. BrokenBroken piecespieces maymay showshow weatheredweathered facesfaces..FracturesFractures uu toto 2525mmmm widewide andand s aces ace nono closercloser thanthan 3030cmcm.. CoreCore recoverrecovergenerallygenerally isis 3535%% oror greatergreater..


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Soft rock : Any rock which flakes on exposure to air or water. Give a very dullSoft rock : Any rock which flakes on exposure to air or water. Give a very dullsound when struck with pick or bar. Core recovery generally is less than 35% orsound when struck with pick or bar. Core recovery generally is less than 35% orgreater but SPT more than 50.greater but SPT more than 50.

Description of rock (BS 5930).Description of rock (BS 5930).

ColourColour

Grain size ( Tab. 9)Grain size ( Tab. 9)

Texture and structureTexture and structure

State of weatheringState of weathering

Rock Name (in capital : Tab. 9)Rock Name (in capital : Tab. 9)

StrengthStrength

Others.Others.

RQDRQD

RQD(%)RQD(%) Soundness of Rock Soundness of Rock

9090 -- 100100 ExcellentExcellent

7575 -- 9090 GoodGood

5050 -- 7575 FairFair

2525 -- 5050 PoorPoor

< 25< 25 Very PoorVery Poor

ermerm n ax a ompress ve reng mn ax a ompress ve reng m

Very WeakVery Weak < 1.25< 1.25

WeakWeak 1.251.25 5.05.0

Depending on moisture ,Depending on moisture ,anisotrophy and testanisotrophy and testprocedureprocedure

o era e y eao era e y ea .. ..

Moderately StrongModerately Strong 12.512.5 50.050.0

StrongStrong 5050 -- 100100

ery rongery rong --

Extremely strongExtremely strong > 200> 200


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2 TYPES OF SAMPLE :2 TYPES OF SAMPLE :--

n s ur en s ur e :: oo e erm nee erm ne proper esproper es sucsuc asas s rengs reng parame ers,parame ers,consolidation,consolidation, permeabilitypermeability andand parametersparameters whichwhich needneed toto observedobserved asas perper sitesiteconditioncondition..

DisturbedDisturbed :: DoDo determinedetermine physicalphysical propertiesproperties suchsuch asas graingrain size,size, colourcolour,, texture,texture,compactioncompaction properties,properties, remouldedremoulded propertiesproperties andand forfor testingtesting etcetc..

Causes of samples disturbance :Causes of samples disturbance :--

From boring processesFrom boring processes

Driving the sampling toolsDriving the sampling tools

Withdraw of sampling toolsWithdraw of sampling tools

The relief of stresses in the soilThe relief of stresses in the soil

Methods to reduce disturbance :Methods to reduce disturbance :--

B fixin extension ieces at each end of the sam lin tube.B fixin extension ieces at each end of the sam lin tube.

For soft sensitive soil use piston samplerFor soft sensitive soil use piston sampler

Sealed sample to reduce moisture losses.Sealed sample to reduce moisture losses.

Sample identificationSample identification..


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TheThe amountamount ofof samplesample disturbancedisturbance dependsdepends onon severalseveral factorsfactors asas

followsfollows::-- ape o cutt ng e geape o cutt ng e ge

Area of container relative to area of soil.Area of container relative to area of soil.

AArr =( D=( Doo22 DDii

22 ) / D) / Dii22 Ar < 0.01Ar < 0.01

..recoverrecover lengthlength andand makemake itit lessless thanthan pushpush lengthlength..

A measure of disturbance is called a recovery ratioA measure of disturbance is called a recovery ratio

LLrr = Length Recovered / Length Pushed= Length Recovered / Length Pushed

LLrr < 1.0< 1.0 -- soil in compressionsoil in compression

LLrr > 1.0> 1.0 -- soil in expansionsoil in expansion

If LIf Lrr not equal to 1.0not equal to 1.0 -- sample are disturbedsample are disturbed

Soil character itself. If the soil is highly sensitive, insitu testingSoil character itself. If the soil is highly sensitive, insitu testingwill be dominant.will be dominant.


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FIELD IDENTIFICATION ANDFIELD IDENTIFICATION ANDDESCRIPTION OF SOILDESCRIPTION OF SOIL

Soil descriptions are made from washed and disturbed samplesSoil descriptions are made from washed and disturbed samples

recovered from the boreholes.recovered from the boreholes.

The soil name is based on particle size distribution and plasticity,The soil name is based on particle size distribution and plasticity,..

According to BS 5930, soil samples are described with each element ofAccording to BS 5930, soil samples are described with each element ofthe descriptions having a fixed position within the overall description:the descriptions having a fixed position within the overall description:-- a)a) Consistency (cohesive) or RD (non cohesive)Consistency (cohesive) or RD (non cohesive)

bb Fabric and Fissurin if distin uishableFabric and Fissurin if distin uishable

c)c) ColourColour

d)d) Subsidiary constituentSubsidiary constituent

ee An ularit or radin of rinci al soil t e for coarse rained soilAn ularit or radin of rinci al soil t e for coarse rained soil

f)f) Principal soil type (in capital letter)Principal soil type (in capital letter)

g)g) More detailed comments on constituents or fabric.More detailed comments on constituents or fabric.

EG.EG.

Dense (a) Brown (c)Dense (a) Brown (c) Fine to Coarse (e)Fine to Coarse (e) Angular (e) GRAVEL (f)Angular (e) GRAVEL (f)

Very Stiff (a) Greenish blue (c) Sandy (d) CLAY (f) With some rounded gravel (g)Very Stiff (a) Greenish blue (c) Sandy (d) CLAY (f) With some rounded gravel (g)


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The following should be used when describing subsidiaryThe following should be used when describing subsidiarycomponents of soils:components of soils:--

DescriptiveDescriptive Subsidiary Component by WeightSubsidiary Component by WeightTermTerm

Sand andSand and Coarse SoilCoarse Soil Fine SoilFine Soil

FinesFines

Coarse ParticlesCoarse Particles

SlightlySlightly 5%5% 5 %5 % Not UsedNot Used

SubsidiarySubsidiaryAdjectiveAdjective

55 20 %20 % 55 15 %15 % 3535 65 %65 %

VeryVery 20 %20 % 1515 35 %35 % Not UsedNot Used

GEOTECHNICAL REPORT GUIDELINE

Executive Summary. Brief to the point summary not exceeding one page of findin s and desi n recommendations

Terms of Reference. Outline terms of reference and scope, identify requestingsource. Find out geotechnical requirements from the project manager, structuralengineer or the geometric designer at the beginning of the assignment and keeptrack of changing requirements thus terms of reference.

Background information/ review of existing data. Provide site description.Describe, topography and geology (in terms of engineering significance andengineering properties), seismic ground motion data, lab data, groundwater andra nage n orma on. rov e oca on map, a ona opograp c er es : ,

map reference, e.g. 92B/12, Longitude and Latitude, Universal Transverse Mercatorcoordinates if possible. Provide plan profile where applicable, site history if available.


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Literature References

Provide a list of references used in the preparation of the report.

Correspondence Soils & rock core logs (make sure standard disclaimers are, ,

for new roads, pit development plan, drawings, plan & profile, photos.

Reports must be signed and stamped both by the author and the reviewer. It is theres onsibilit of the author and the reviewer to determine the a ro riateness andaccuracy of input data and the correctness of the computed results. Use of computer programs does not free the Professional Engineer or the Professional

Geoscientist from this res onsibilit .

Surface InvestigationSurface Investigation

Site inspection of existing earth structure, slabs and foundation nearby.Site inspection of existing earth structure, slabs and foundation nearby.

Study Topographical, geological, hydrological map, data. Etc.Study Topographical, geological, hydrological map, data. Etc.

, ., .

Sub surface InvestigationSub surface Investigation

Test PitsTest Pits

Sam lin and Lab TestSam lin and Lab Test

LogLog

InsituInsitu TestingTesting

or ng esor ng es

Rotary boringRotary boring

Percussion boringPercussion boring

LogLog

Lab TestLab Test


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Engineers should allow or apt with changes during constructionEngineers should allow or apt with changes during construction

of foundation at site.of foundation at site.ternat ve es gn nee to e n an w enever t ere areternat ve es gn nee to e n an w enever t ere are

changes during this stage.changes during this stage.

,,as the delay in making decision will hold or retarding the processas the delay in making decision will hold or retarding the processof construction.of construction.

This is a stage where foundation engineers are really tested inThis is a stage where foundation engineers are really tested in

their knowledge integrity.their knowledge integrity.This is also a stage where reliability of SI data is known.This is also a stage where reliability of SI data is known.

To validate the design, load test need to be carried out. TheTo validate the design, load test need to be carried out. Thedesigner may choose to have them conducted either before ordesigner may choose to have them conducted either before or

..

The first alternative permits development or revision of designThe first alternative permits development or revision of design..

The second saves expenses on mobilisation but may lead to delayThe second saves expenses on mobilisation but may lead to delayif the results is unsatisfactoril .if the results is unsatisfactoril .


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PILE LOAD TEST ANDPILE LOAD TEST ANDINTERPRETATIONINTERPRETATION


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The time lapse is sufficient for excess pore water pressure toThe time lapse is sufficient for excess pore water pressure toss pates.ss pates.

Pile in cohesive soils should be tested after sufficient lapse forPile in cohesive soils should be tested after sufficient lapse for..

This time lapse is commonly in the order of 30 to 90 days givingThis time lapse is commonly in the order of 30 to 90 days giving..


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LOAD

5mm

mm

6.

12.

ment

DL

38mm

settl


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From point O to a the capacity is based on the skin resistance plus any small point contribution.From point O to a the capacity is based on the skin resistance plus any small point contribution.

From oint a to b the load ca acit is the sum of the limitin skin resistance lus the ointFrom oint a to b the load ca acit is the sum of the limitin skin resistance lus the oint

capacity.capacity.

From point b the curves becomes vertical as the ultimate point capacity is reached. Often the verticalFrom point b the curves becomes vertical as the ultimate point capacity is reached. Often the vertical

asymptote is anticipated and the test terminated before a vertical curve branch is established.asymptote is anticipated and the test terminated before a vertical curve branch is established.

250N

1600-250 = 1350 N


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Generally the proper design requires the following:Generally the proper design requires the following:--

1.1. Determine the building purpose, probable service lifeDetermine the building purpose, probable service lifeoa ng, type o ram ng, so pro e, construct on met o soa ng, type o ram ng, so pro e, construct on met o sand construction cost.and construction cost.

.. ..

3.3. Making the design, but ensuring that it does not successivelyMaking the design, but ensuring that it does not successively

that produces a tolerable risk level to all parties, the public,that produces a tolerable risk level to all parties, the public,

the owner and the engineer.the owner and the engineer.

ADDITIONAL CONSIDERATION INADDITIONAL CONSIDERATION INFOUNDATION DESIGNFOUNDATION DESIGN

Adequate depthAdequate depth

Depth of foundation to be below seasonal changeDepth of foundation to be below seasonal change

Considering problematic soilConsidering problematic soilCompressive strength considerationCompressive strength consideration

Protection of foundation against natural causesProtection of foundation against natural causes

Sustainable to changesSustainable to changes

Buildable or limitation.Buildable or limitation.

Apt to local environment standard.Apt to local environment standard.


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Based from Neoh C.A, the choice of the foundation designs areBased from Neoh C.A, the choice of the foundation designs are

considered from:considered from:1.1. oa s per co umnoa s per co umn

2.2. Bearing type either end or skinBearing type either end or skin

3.3. ear ng ayerear ng ayer

4.4. Type of Intermediate layerType of Intermediate layer

5.5. Location of water level.Location of water level.

Assess Foundation BasePROCEDURE FOR THECHOICE OF FOUNDATIONTYPE FOR A SITE

ssess rounConditions and Type ofStructures

YESAre pilenecessary

ChooseShallowFoundation

TechnicalConsiderationsfor Different Pile

Types:-

1. Ground Condition

2. Loading Assess construction programme for each

3. EnvironmentalConsiderations

4. Site and PlantConsiderations

on program consideration

Make overall rankin of each ile t e5. Safety

List all technically feasible pile types

based on technical, cost andprogramme considerations

based on technical consideration.

Submit individual and overall rankings of each piletype to client and make recommendation on most

suitable pile type.

rank them based on cost consideration.


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advance foundation engineering design principles

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