Foundation engineering all units including

Short notes for foundation engineering

1. UNIT 1:

2. GeotechnicalEngineering–II
BTechCivilEngineering–6
th
Semester
Course Materials
Chapter I: SOIL EXPLORATION

3. Soil Exploration WHAT??WHY??
Forconstructionofanystructure,aknowledgeabouttheground
conditionsisimportant.Thesoilstructure,capacityandbehaviour
undervariousloadingconditionswillhelpdesignthesubstructuresand
retainingstructures,andtosuggestremedialactionstoimproveground
conditionswhenrequired.
Explorationinsoil-involvesasitevisit,quickvisualinspectionand
detailedteststodeterminethebehaviour
"Thefieldandlaboratoryinvestigationsrequiredtoobtainnecessary
dataregardingthesoil,forproperdesignandsuccessfulconstruction
ofanystructureatthesitearecollectivelycalledsoilexploration.”

4. ObjectivesofSoilInvestigation
1.Toassessthegeneralsuitabilityofsite
2.Todeterminethebearingcapacityofthesoil
3.ToSelectthetypeanddepthoffoundationforagivenstructureEstimatemax.probable
settlement(totalanddifferential)
4.Investigatethenatureanddepthofeachstratumandassessrequiredproperties
5.Toselectthesuitableconstructiontechnologybasedonavailabilityandeconomy
6.Toknowthegroundwaterconditions
7.Predictpossibledifficultiesandproblemsinsiteandsuggestremedialactions
8.Ensuresafetyofexistingstructures
9.Investigatetheoccurrenceofanynaturalormanmadechangesinconditionsandthe
resultfromthosechanges
This information obtained by -
Drilling holes, taking samples,
finding Index and Engineering properties
Conducting some field tests

5. HOWTODOIT??
For any project, soil investigation Costsof 0.2%-Even1% insomecases-Soproper
planningmust!!
Dependson
Typeandimportanceofstructure
Natureofsubsoil(stratavariability)
Budget/economy
Involves
Locationanddepthofboreholes
Teststobedone,andtestmethods
Samplingmethods
3importantphases:Planningexecutionreportwriting
DetailedinformationLessuncertaintylaterless factorofsafety(orfactor of
Ignorance!!)lesscostof construction

6. Stages in Subsoil Exploration
Reconnaissance
Preliminary Investigation Detailed investigation
Involvesasitevisitandvisual
inspectionsatthesite
Rough Idea about work that how to
start
Toassesstheneedfordetailedinvestigation
Determination ofdepth,thickness, extentand
compositionof eachlayer
DepthofbedrockandGroundwatertablealsostudied
Labandfieldteststoassessbasicproperties
Chemicaland bacteriologicaltestsifneeded
Methods:
Boreholes,testpits, Conepenetrometer, Sounding
rods, Geophysicalmethods
Mainlyforbigprojects-Dams,bridges,multistoried
buildings
Alsofornewlybuiltupsoil
Involvesextensiveboringprogrammesampling
laband fieldtesting
For smallprojectsonsitewith uniformstrata or
clearhistory,info. from reconnaissanceand prelim.
investigationsufficient
Uniformstrataboreholesatregularspacing

7. Some Visual indicationsabout site
Random depressionsandmarkedirregularitiesSink holes
Wrinklingofsurfaceonhillsidesoil creep
Shaftsorheapsofmineralwasteabandoned mines
Lowlyingflatareasriverorlakebed
Springs,wellsHighwatertable
MarshygroundHighwatertablewithpoordrainage

8. BOREHOLE (BH)
Depth,lateralextentand numberof boreholesdata are importantfor any soil
investigation before construction
DepthofExploration:Dependsontypeofstructure,intensityofload,soil
profile,andthephysicalpropertiesofsoil
(Basedonfewtrialpitsandtestborings,oranexperiencedperson’sjudgement)
SignificantDepth:
"Depthuptowhichthe superimposedloadscanproduceconsiderable settlement
andshearstresses"
Generally,significantdepthisthat atwhich verticalstressis20%( or 1/5
th
)of
the load intensity(considering2:1 loaddistribution,stressat D=1.5Bisnearly
1/5
th
)
Depthofexplorationmust be greaterthanorequaltosignificantdepth

9. Depth of exploration for some structures
(Code: IS1892-1979)

10. Forhospitalsandofficebuildings,thefollowingrulecouldbe useto determineboringdepth
Deepexcavations,thedepthofboring shouldbeat,least1.5timesthe depthof excavation.
The minimum depth of core boring into the bedrock is about 3m. If the bedrock is irregular or
weathered, the core borings mayhave to be extendedto greater depths.
If there are weak zones at depth ( zone of volume change, seasonal variations, swellingand
shrinkage),boringshouldbe continuedbelow thisweakzones.
Alwaysensure:Explorationdepthsuchthat loadcanbe carriedbythat stratum
withoutundesirable settlementand shearfailure

11. Lateralextentofexploration
Number and spacing of boreholes must be such as to reveal any major changes in thethickness,depth
andpropertiesofstrataover the baseareaofthestructure anditsimmediatesurroundings.
Moreuniformstrata-lessno: ofBH andmorespacingcanbe adopted
Erraticvariation-moreno: ofboreholesatreducedspacing
Whereverpossible,BHmustbesunkclose totheproposedfoundation, especiallyinsoilsof
erraticvariation
Whenlayoutnotplannedbefore-Best patternisevenlyspaced grid of BH
ConepenetrationtestscanbeperformedTevery50mintervals
Gravellyandboulderousstrata-CPTnot feasible,hencegeophysicalmethods adopted

12. Lateral extent of exploration (IS: 1892)

13. Direct/Open excavation (<6m)
•Drifts
•Shafts
•Pits
•Trenches
Semi direct/Boring
•Auger boring
•Wash boring
•Percussion boring
•Rotary boring
•Core Drilling
Indirect methods
•Geophysical methods
•Sounding rods
DifferentMethodsofExplorationinsoils

15. Open excavation (for depth <6m)
Trialpits-1.2mX1.2m(IS 4453-1967)
Depth>3mlateralsupport
Properventilationanddewateringifnecessary
Trenches-longshallowcontinuouspit,exposing aline
Drifts(adits)-horizontaltunnelsalonghillside,especiallyforrocks
Min1.5m(b)X2m(h)
Lateralsupportifunstable
Generallyexpensive
Helpstoestablishminimumexcavationlimitstoreach soundrocks,
&tolocatefailureandshear zones
Shafts:Largeverticalholes(min2.4mwidthordiameter)
ForD>4m
Propersupportandventilationrequired

16. Boringrefersto advancingahole intheground,usedespeciallywhenD>6m
It is asemi directmethodofexploration
Necessity:
Toobtainrepresentativesoilandrock samplesfor laboratorytests.
Toidentifythegroundwaterconditions.
Performanceofin-situteststoassessappropriatesoilcharacteristics.
Extensometersandpressuremeters canbeinstalled
Results Borelogandsubsurface profilescan be obtained
Drillingborehole takingsamplestestingBorelog
Types:(1)Augerboring(2)Washboring(3)Percussiondrilling(4)Rotarydrilling(5)Coredrilling
Boring methods

17. AugerBoring
Simplest and most common method of boring for small projects in
soft cohesivesoils.–Fast,economical,light,inexpensiveand
flexible
Augeradrillforadvancingholes
Has ashankwithcrosswisehandletoapplytorque
Thelengthof theaugerbladevariesfrom0.3-0.5m.
Diameterofcentralrodalmost18mm
Augerheldverticallyanddrivenbyapplyingtorque,eithermanually
ormechanically
Drivingforce:Torqueonhandle+downwardpressingforce
The augerisrotateduntilitisfullofsoil,thenitis withdrawnto
remove thesoilandthesoiltypepresentatvariousdepthsisnoted.
Handaugersandmechanicallyoperatedauger
Postholeaugers:fortakingsamples whenholeisalreadydug/driven

18. Hand-operatedcan be made upto about 6mdepth
Usually used for shallow depth applicationsrailroad,highwaysetc
Highly disturbed samples (but better thanotherboringmethods)usedfor
classification purpose and basic tests only
PoweroperatedThe power required to rotatethe auger depends
onthe typeand size ofauger and the typeof soil.
can be made uptoabout 12m depth
Downwardspressureappliedhydraulically,mechanicallyorbydead
weight

19. Mechanical/Power operating augers
Outcomes of Auger boring:
Disturbed soil we get
Below Water table not possible
Changes in soil strata not known
Hand operatingaugers

20. WashBoring
Fastand simpledo works at > 12 m depths
Casingpipe–5-10cmdiameterdriventothegroundfirst,
uptocertaindepth (~1.5m)
Washpipe-lower diaupperendconnectedto watersupply
system,andlowerend tochiselshapedchoppingbit
Water with high pressure pumped through hallow boring rods
released from narrowholes in a chisel attachedto thelower
endoftherods.
Drivingforce:jettingactionofwater+choppingaction ofchisel
Slurrycomesup throughannularspacebetweencasingpipeand
wash pipetakenintubsettlessamplescanbetakenif
required
Furtheradvancementof holecanbedonebyraisingandlowering
ofchoppingbit
Casingscanbe extendedordrillingfluidscanbe pumpedinstead

21. Outcomes:
Highlydisturbedsamples
Finerparticles(clay,loametc.)wontsettle,and
heavierparticlesnot brought up
Exactstrataidentificationnotpossibleduetomixingof
soilparticles
Slowincoarsegrainedand stiffsoils
Not effectiveinhardsoils,rocks,boulders
Canbeusedinmosttypeofsoilbuttheprogressisslowin
coarsegravelstrata
Someindicationsaboutstratafromslurrycolouranddrill
penetrationresistance
Itisonlyusedforadvancingtheboreholetoenabletube
samplestobetakenorfieldtesttobecarriedatthehole
bottom.
WashBoring

22. WashBoring

23. Percussiondrilling
Consistsofbreakingupoftheformationbyrepeatedblows
fromabitorachisel.
Watershouldbeaddedtotheholeatthetimeofboring,and
thedebrisremovedatintervals.
Wheretheboringisinsoilorintosoftrocksandprovided
thatasamplercanbedrivenintothem,coresmaybe
obtainedatintervalsusingsuitabletools
Butinsoils,thematerialtendstobecomedisturbedbythe
actionofthismethodofboringandforthisreason,thesample
maynotbemuchreliable
Asthesemachinesaredevisedforrapiddrillingby
pulverizingthematerial,theyarenotsuitableforcareful
investigation.
Theonlymethodsuitablefordrillingboreholesin
boulderousandgravellystrata.

24. Change in soil characteridentifiedbycomposition
of outgoingslurry
Disadvantages:
Bottommaterialhighlydisturbeddue toheavyblows
Expensive-requireslarge equipments
Minorchangescannotbedetected fromtheslurry
Uneconomicalforholesof diameter<10cm
Alsousedfordrillingtubewells
Percussiondrilling

25. Rotarydrilling
Similar towashboring, buthole advancedbyrotatingahollow
drillrodwith cuttingbitatthelowerend and drill headat upper
portion
Primarilyintendedfor investigationin rock,but also usedin soils.
Waterordrillingfluid ispumpeddownthehollowrodsand passes
under pressure throughnarrowholesinthe bit or barrel
Drillingrodrotatescutting bitshearsoffchipsof materialmaterials
removedby circulatingdrillingfluids
Functionsofdrillingfluid:
coolsandlubricatesthedrillingtool
carriestheloosedebris tothesurface betweentherods andtheside
ofthehole.
Providessomesupporttothesides of theholeifno casingisused .
Usefulforhighlyresistantstrata and forclay,sand,rocks
Notforgravellysoilsincetheykeeprotatingbeneathdrill rod

26. Twoformsofrotarydrillingopen-holedrillingand coredrilling.
Open-holedrillinggenerallyusedinsoilsandweakrockjustforadvancingtheholeThe
drillingrodscanthenberemovedtoallowtubesamplestobetakenorin-situteststobecarried
out.
Core drillingusedin rocksandhardclaysthediamondor tungstencarbidebit cutsan
annularhole in thematerialand an intactcoreentersthe barrel,toberemovedasasample.
Typicalcorediametersare41,54and76mm,butcanrangeupto165mm.
Suitablefor holesof15-20cmdia;uneconomicalfordiameter<10cm
Advantages:progress muchfaster, anddisturbanceofthesoilbelowtheboreholeisslight.
LimitationsThe method isnot suitableif the soil containsahighpercentageof
gravel/cobbles,astheytendtorotatebeneaththebitandarenotbrokenup.Thenaturalwater
contentof the materialisliabletobe increaseddueto contact withthe drillingfluid
Rotary drilling

27. Rotarydrilling

28. Coredrilling
Atypeofrotarydrillingusedforrocks
Similartorotarydrilling,butprovidedwithasharpercuttingedge(madeofdiamondortungsten)
DrillingrodwithcorebarrelfittedwithdrillingbitRotateddrillbitadvancesdowncutsan
annularholearoundanintactcore.
Corethenremovedandretainedbycorelifter
Waterpumpedcontinuouslytocoolthedrillingbit,andbringupthedisintegratedmaterials
Important:ensurethatboulders,orlayersofcementedsoilsarenotmistakenforbedrock.This
necessitatescoredrillingtoadepthofatleast3minbedrockinareaswherebouldersareknowntooccur.
Forshearstrengthdetermination,acorewithdiametertoheightratioof1:1isrequired.
Rockpiecesmaybeusedfordeterminationofspecificgravityandclassification.

29. Coredrilling

30. Undisturbed samples
The natural state of soil structure
remain as it is
To find: Shear parameters,
Compressibility, Permeability, Field
Moisture-Density, Void ratio
Non representative samples
•Mineral composition is
changed
Representative samples
•Structure get disturbed but mineral
composition is same
(Used to find index properties)
Samples
Disturbed samples
The natural state of soil structure get
disturbed while sampling
To find: Atterberglimits, GSD,
Compaction, SG
SAMPLINGTOOLSANDSAMPLERS

31. Cuttingedge Insidewallfriction
Methodofapplyingforce Non-returnvalve
Designfeaturesaffectingdegreeofdisturbance

32. Designfeaturesaffectingdegreeofdisturbance
InsideClearance:C
i=(D
3-D
1)/D
1X100
•Internal dia of cutting edge must beslightly less
than internaldiaofsamplingtube
•Itallowselasticexpansionofthesampleand
reduces frictionaldrag
Forundisturbedsample,C
i=1to3%
•Outsidediaofcuttingedgemust bemore than
outerdiaoftube
•To facilitate the withdrawal of sampler from soil,this
must beleast
Forundisturbedsample,Itshouldlie between 0 to 2%
( But C
o must not be much morethanC
i)
Outsideclearance:C
o=(D
2–D
4)/D
4X 100
1.CUTTINGEDGE

33. 2 2 2
A
r=RatioofMaximumcross-sectionalareaofthecuttingedgetototalareaofthe soil sample
Shouldbeaslow aspossible,consistentwithstrengthrequirementof sampletube
Generally,forUndisturbedsamples:Area ratiolessthan 10%
ArearatioA
r=(D
2-D
1)/D
1 X 100
2. Inside wall Friction: Theinsidewallshouldbesmooth.
Canbedoneby:
Applyingoilinsidethetube
Providingsmooth finishtosampletube
Ensuringsuitableinsideclearance

34. 3.DesignofNonreturnValve:
Thesamplermusthavealarge orificetoallowquickescapingof air,waterorslurry.
4.Methodofapplyingforce:
Therateofadvancementandmethod ofapplicationofforce controlsthesample
disturbance.
Thesamplermust bepushednotdriven
5.Recoveryratio:
R=L/H
L = length of sample within the tube; H= depth of the penetration of sampling tube
It shouldbe 96-98%forgoodundisturbedsample

37. Opentubesampler/Shelbytubes
Thinwalled, Undisturbed samples
Madeof seamlesssteelwithchamferedlowerendforeasypenetration
Outsidedia:45mm,65mm,80mm,100mmetc.
Thickness:1.25-3.15mm
Commonlyused:outsidedia 50.8mm,inside dia 47.63mm=>Area
ratio~10% (always< 15%)Undisturbed
Casingdrivenuptosamplinglevelholeiscleanedsamplingdone
Lengthoftube:5-10timesdia forsandysoils,and10-15timesdia for
clayeysoils
Samplerpushed,not drivenleastdisturbance
Suitableinverysofttomediumsoftclays andsilts

38. Splitspoonsampler
3parts
Drivingshoeatbottom-75mm long
Steeltube,splitlongitudinallyinto2halves-450mmlong
Couplingatthetop-150mmlong
Procedure:
Sampler lowered to the bottom of the borehole by attaching it to the drill rodThen driven by forcing it
into the soil by blows of a standard hammerSampler assemblythentakenoutcoupling andriving
shoeremovedsteeltube splitinto halvessamplestaken
StandardpenetrationTest:UsessplitspoonsamplerHammer63.5Kg;heightoffall 762mm
Samplesgenerallytakenatintervalsof 1.53m
Commonlyuseddia:Outsidedia 50.8mmandinside dia 34.9mm=>Area ratio> 100%highly
disturbedsamples
Whenusedin sand,―springcore catcher‖placedinside thesplittube,toretainthesample

40. Pistonsampler
Consistsoftwoseparateparts,(a) the samplecylinderand
(b)thepistonsystem
Pistonfitstightlyinthesamplercylinderandisactuatedseparately.
During the driving and till the start of the sampling operation,thebottomof
thepiston flushwiththecutting edgeofthesampler.
Atthedesiredsamplingelevation,thepistonfixedintothegroundandthe
samplercylinderforcedindependentlyintotheground,thuspunchingasample
outofthesoil
Thepistonpreventswateranddirtfromenteringthetubeduringthelowering
operation.Italsokeepstherecoveryratioconstantduringthepunch.
As the sampler tube slides past the tight fitting piston during the sampling
operation, a negative pressure is developedabovethesample,whichholds
backthe sampleduring withdrawal

42. Handcarvedsamples
Acylindricalcontaineropenat both the ends is
used for sampling.
Thesoilistrimmedtoshapeat thebottomof
thetestpit
One end of container is closed andinverted
overthesoilchunk and the soil sample is
removed usingspatula
Thismethodissuitablefor cohesivesoil.

43. GEOPHYSICALMETHODS
Indirectmethod: Fromsurfacemeasuringcertainphysicalpropertiesinterpretthe
subsurfacesoilproperties
Basedonthe changesin gravitational,magnetic,electrical,radioactiveor elasticpropertiesof
thedifferentelementsof thesubsoil
Gravitational, magnetic and radioactive propertiesminor change near surface
Resistivitymethodbasedon theelectricalpropertiesandtheseismic
refractionmethodbasedontheelasticpropertieswidelyused
ADVANTAGES: simple, fast, economical, portable instruments, large area easilyinvestigated
APPLICATIONS:subsurfacesoil,mineralores,geologicstructures,groundwaterstudies

45. Electrical methods
Principle
Electricmethodsarebasedonthefactthatthesubsurface
formation, structures,oredeposits,etc.possess
different electricalproperties.
Numerousandversatileapplicationsgroundwaterstudies,
subsurface structuresandmanyothers
Propertiesconsidered:electricalresistivity,dielectricconstant
Types:electricalresistivity method,electromagnetic
methods,selfpotential methods andinduce polarization
method
Subsurfacesoil explorationelectricalresistivitymethod
used
Electrical Resistivity Measurements

46. ElectricalResistivitymethod-ProsandCons
Advantages
Itisaveryrapidand economicalmethod.
Itisgoodupto30mdepth.
The instrumentationof thismethodis verysimple.
Itisanon-destructivemethod.
Disadvantagesofthismethodare:
Itcan onlydetectabsolutelydifferentstratalikerockandwater.
Itprovidesnoinformationaboutthesample.
Culturalproblemscauseinterference,e.g.,powerlines, pipelines,buriedcasings, fences.

47. SeismicMethods
ControllingProperties:Elasticproperty
Principle:
Subsurface soil androck formations bear different elastic properties
seismicwaveshavedifferentvelocitiesindifferenttypesofsoils(orrock)
wavesrefractatboundaries
Artificialimpulseproducedeitherby detonationofexplosiveor
mechanical blow with a heavy hammer at ground surface or at the shallow
depth within a hole.
Assumesthatsoilgetsdenserwithdepthandhencevelocityofseismic
waves increasewithdepth.
Geophonesfixedatsuitableintervalsontheground
Geophone

48. Seismic wavescompressivewaves,shearwavesandsurfacewaves
compressivewavesrecorded
Thesewavesareclassifiedasdirect,reflectedandrefractedwaves.
The directwavetravelinapproximatelystraightlinefromthesourceof impulse.
The reflectedandrefractedwaveundergoesachangeindirectionwhen they encounter a boundary
separating media of different seismic velocities
Thismethodismore suitedto theshallowexplorationsforcivil engineeringpurpose.
Assumption:
•Allsoillayersarehorizontal.
•Thelayer issufficientlythicktoproducea response.
•Eachlayerishomogeneousandisotropic.
•Velocityshouldincreasewithdepth,followingtheSnell's law

49. Seismic refraction test

52. Spacingofgeophones:dependuponamountofdetailrequiredandthedepthtobeinvestigated;
Generallyspacedsuchthattotaldistancefromfirsttolastgeophoneis3-4timesthedepthof
investigation
Uptocertaindistance (criticaldistance,sayL1),directwavesreachfirst from layer1.
AfterL1,therefractedwave willreachfirstsinceitpassesthroughadenser layer2.
Soat L1,both reachessimultaneously.-onetravellingL1distance atV1and other,gettingrefracted
fromlayer2,ietravelling2H1atV1andL1atV2. i.e,
??????1
=
2??????1
+
??????2
??????1 ??????1 ??????2 ??????2
soH1=(
V2−V1
*
??????1
)
2
Applications:
Depthandcharacterizationofthebedrocksurfaces
Buriedchannellocation
Depthofthewatertable
Depthandcontinuityofthestratigraphyinterfaces
Mappingoffaultsand otherstructuralfeatures.

53. Advantages
Complete pictureof stratificationof layerupto 10mdepth.
Simple equipmentsandeasyexecution
Littleprocessingrequired
Providesseismicvelocityinformationforestimatingmaterialproperties.
Providesgreaterverticalresolutionthanelectrical,magnetic,or gravity
methods.
Data acquistionrequiresverylimited intrusiveactivityisnon-destructive.
Cannotbe usedwhenhardlayer overliessoftlayer
Cannotbe usedinareaslikeconcreteorbitumen
Presenceofburiedconduitsandservices
Cannotbeusedinfrozenlayers
Highcost, and skilledlabour
Disadvantages

54. Roleofgeophysicalmethodsinsolvinggeotechnical problems
Gravitationaland magneticmethods inmining and petroleumengineering.
Geotechnicallimiteduseforsurvey ofunconsolidatedsedimentsoverthedense
bedrock.
Magneticmethodisappliedtolocatedikes, faultsand buriedpipesand other concealed magneticmetal
works.
Seismicandresistivitymethods:
Fordamandbridgesites,tolocatedepthofthesolidrock
Fordesignoftheunderwaterfoundation
Forbuildingsitestolocatehardrockstrata/softstrataseismicmethodis used.
Slopedesignandthelandslideinvestigation
Tolocatetheshallowdeposits
Groundwaterinvestigation
Inthe insituevaluationofconcrete,geophysicalmethodsareusedto determineuniformityofconcrete.

55. Standard Penetration Test (SPT)
Some Fields tests

56. Link: https://www.youtube.com/watch?v=DjWDOqQjsyQ

58. Static cone penetration test
Cone resistance, static load @ 10mm/sec,
to a depth of 35mm each time

59. Dynamic cone penetration test
https://www.youtube.com/watch?v=_pjOs7NqntQ
Cone resistance is measured by measuring no of blows
for driving cone for specific distance

60. Plate load test

61. PLT (Cont..)
https://www.youtube.com/watch?v=QuE4tEK-5iY

66. Pressure meter test

67. Vane shear test (Field)

68. 12

70. 70

71. 71

73. 1.Undisturbedsamples inseamless tube:
Endscutandremoved (atleast2.5cm)waxfillspacewithsaw dustlid
2.Undisturbedsamplesnotintube:
Coveredwhollywith waxmetalcontainertight lidadhesive tape
3.Disturbed:
Immediatelyplacedin glassjarairtightcontainer
4.Rocks:
Label-referenceno: directlyonsurface ortapewoundedwrappedin paperbox
Rockcorepreserve whole corecoreboxwithseparatecompartments
Labelingimportant
Transportation:Linerorcontainersplacedinwoodenboxwithseparate partitionspacked with fillers
Handling,preservationand transportationofsamples

74. Extrusion:
Take outchipoffwax
Pistonextrusion(ifproperlyoiled)disturbssoftclay
Supportthesample
Extrudein onedirectionfromcuttingedgetotop
Storeincoolhumidplace
Rock:keptintoboxensure noendtoend turning

75. Labeling:Labelplacedinsidelidontop

76. SUBSOILINVESTIGATIONREPORT
Laststepinasoilinvestigation
Boreholedata,site observationsandlabresults
Eachborehole-identifiedbycode
Mainly 4 parts: Project details; Results; Analysis and possible solution; Recommendations(Allowable
soilpressureand expectedsettlements)
Borelogalldetailsof the boreholedepth,stratavariationobtained,
propertiesofeachstrata,watertableetc
Subsurface profiledata obtained from a series of boreholes vertical sectionthrough groundalong
lineofexplorationIndicateboundariesof strata,theclassificationof soil type,and mainproperties

77. Contentsofsubsoilinvestigationreport
1.Scopeof theinvestigation
2.Proposedstructure
3.Locationdescriptionsofthe sitestructures nearby,drainageconditions,
vegetationandanyotherfeaturesuniquetothesite
4.Geologicalsettingof thesite
5.Detailsofthefieldexploration—numberofborings,depthsofborings,typesofboringsinvolved,andsoon
6.Ageneraldescription ofthesubsoilconditions-fromlabandfieldtests
7.Thewater-tableconditions
8.Recommendations regarding the foundation, the allowable hearing pressure, and any specialconstruction
procedure thatmayhe needed;
9.Conclusionsandlimitationsoftheinvestigations

78. SubsoilExplorationReport-Graphical presentations
The followinggraphicalpresentationsshouldhe attachedtothereport:
1.Asitelocationmap
2.Aplanviewofthelocationoftheboringswithrespecttothe proposedstructuresandthosenearby
3.Boringlogs
4.Laboratorytestresults
5.Otherspecialgraphicalpresentations

81. Thank you…..