In-situ Testing – Current Trends in Geotechnical Investigations

1. Sanjay GuptaSanjay Gupta
CENGRS Geotechnica Pvt.Ltd.CENGRS Geotechnica Pvt.Ltd.
New DelhiNew Delhi

2. Modern GeotechnicalModern Geotechnical
EngineersEngineers
Face challenges to solve various problemsFace challenges to solve various problems
related torelated to
–– InfrastructureInfrastructure
Space utilizationSpace utilization
Underground constructionUnderground construction
HighwaysHighways
IndustryIndustry
Power sectorPower sector
Hill area developmentHill area development
Difficult strata conditionsDifficult strata conditions

3. Performance of the Structure
should be as envisaged.
Engineering SolutionEngineering Solution
Higher factor of ReliabilityHigher factor of Reliability
EconomicalEconomical
PracticalPractical
NEED to model inNEED to model in--situ behaviorsitu behavior

4. Presentation CoversPresentation Covers
Current TrendsCurrent Trends ---- InIn--situ testingsitu testing
–– For higher factor of reliabilityFor higher factor of reliability
Modern /Advanced Testing TechniquesModern /Advanced Testing Techniques
–– Static Cone Penetration TestStatic Cone Penetration Test
–– Pressuremeter TestPressuremeter Test
–– Aquifer / Pump Out TestAquifer / Pump Out Test
–– GeoGeo--physical Testphysical Test
Case StudiesCase Studies –– Projects executed byProjects executed by
CENGRSCENGRS

5. Project
Components of
Project
Foundation
GeoProfesional
With Advancement in Technology, We have
Specialists for Various Components
Human Body
Parts of Body
Heart
Cardiologist

6. Current TrendsCurrent Trends
To identify and understand
the actual behavior/condition
Geotechnical
Investigations
BH, DCPT, PLT
CPT, PMT
Pathalogical
Investigations
Blood Tests, Blood
Pressure, etc.
CAT Scan, MRI, etc.

7. FPS Units
MKS Units
SI Units
Mistry Approach
Architect
Specialized Engineers
BH, DCPT, PLT
Cone Resistance (CPT)
Limit Pressure (PMT)
Visual/Personal
Assessment
Transition PhaseTransition Phase

8. Static Cone Penetration TestStatic Cone Penetration Test
Power Plant 20 Tonne Capacity
Near Ayodhya

9. Static Cone PenetrometerStatic Cone Penetrometer
Cone tip resistanceCone tip resistance
Friction jacketFriction jacket
resistanceresistance
Total systemTotal system
resistanceresistance
Friction RatioFriction Ratio

10. SCPTSCPT –– Typical ResultsTypical Results

11. Advantages of SCPTAdvantages of SCPT
Continuous profile with depthContinuous profile with depth
Hydraulically PushedHydraulically Pushed –– human errors minimizedhuman errors minimized
Eliminates sample disturbancesEliminates sample disturbances
Can use Electrical Cone / PiezoCan use Electrical Cone / Piezo--cone with Datacone with Data
loggerlogger
Analyze safe bearing capacity & SettlementAnalyze safe bearing capacity & Settlement
directly for open foundationdirectly for open foundation
Pile capacityPile capacity –– more realisticmore realistic
Quality / compaction controls for embankments,Quality / compaction controls for embankments,
ground improvementground improvement

12. Limitations of SCPTLimitations of SCPT
Not suitable for bouldary strataNot suitable for bouldary strata
Where shallow rock/hard formation isWhere shallow rock/hard formation is
encountered, the utility of the test is limitedencountered, the utility of the test is limited

13. Pressuremeter TestPressuremeter Test
Control
Panel
Gas
CylinderProbe

14. Radially
Expandable Probe
Control Panel
Inner Membrane Outer Cover
Measuring Cell Guard Cell
Water Gas (CO2
) / N2
)
Volume Change Pressures
Measuring Cell
(Water)
Guard Cell
(Gas)
Pressuremeter Test Unit
Inflate by
Coaxial Hose

15. Pressuremeter ProbesPressuremeter Probes
Probes
Rubber Metallic
Soils
(upto 25 bar)
Rocks
(upto 80 bar)

16. Pressuremeter ProbesPressuremeter Probes

17. Pressuremeter ProbePressuremeter Probe
Probe
Calibration
Air Calibration Pipe Calibration
Stiffness of
rubber parts
(Pressure)
Volume loss for
expansion
(cc/bar)

18. Pressuremeter Control PanelPressuremeter Control Panel
M.C. Gauge
Differential
Control
G.C. Gauge
Gas Cylinder
Pressure Gauge
Volumeter
Regulator
Hose
to Gas Cylinder
Coaxial Hose
to Probe

19. ProbeProbe –– Lowering in BHLowering in BH
Probe
NX Casing
Drill Rig

20. Pressuremeter ProbePressuremeter Probe
Note
increased
diameter
in centre

21. PMT Test at Delhi MetroPMT Test at Delhi Metro

22. Typical Test ResultsTypical Test Results
V O L U M E, cc
PRESSURE,bars
0
1
2
3
4
5
6
7
8
9
10
0 200 400 600 800
Corrected Curve
Field Curve
Air Calibration
Pipe Test
SoilSoil RockRock
V O L U M E, cc
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
0 50 100 150 200 250 300 350 400
PRESSURE,bars
Corrected Curve
Field Curve
Air Calibration
Pipe Test

23. Typical PMT Profile (Soil)Typical PMT Profile (Soil)
Borehole No : 1A
0
2
4
6
8
10
12
14
16
0 20 40 60 80 100 120 140
DEFORMATION MODULUS ( kg/cm2
)DEPTHBELOWGROUNDLEVEL,m
0
2
4
6
8
10
12
14
16
0 2 4 6 8 10 12
LIMIT PRESSURE (bar)

24. Results of Soil ClassificationResults of Soil Classification
with Limit Pressurewith Limit Pressure
Soil Classification PL (kN/m2)
Clay 0 – 1200
Silt 0 – 700
Firm Clay or Marl 1800 – 4000
Compressible Sand 400 – 800
Compacted Silt 1200 – 3000
Soft on Weathered Rock 1000 – 3000
Sand and Gravel 1000 – 2000
Rock 4000 – 10000
Very Compacted Sand and Gravel 3000 - 6000

25. PressuremeterPressuremeter –– AdvantagesAdvantages
InIn--situ stresssitu stress--strain behavior of soil andstrain behavior of soil and
rock can be evaluatedrock can be evaluated
Minimum disturbance to inMinimum disturbance to in--situ conditions,situ conditions,
hence quality of results is superiorhence quality of results is superior
More realistic behavior / analysis for openMore realistic behavior / analysis for open
& pile foundations& pile foundations
In weathered rocks, where core recoveryIn weathered rocks, where core recovery
is poor, pressuremeter test is the only testis poor, pressuremeter test is the only test
which can give realistic datawhich can give realistic data

26. PressuremeterPressuremeter –– LimitationsLimitations
Test cannot be conducted in bouldaryTest cannot be conducted in bouldary
stratastrata
In sandy strata, difficult to conduct the test,In sandy strata, difficult to conduct the test,
due to borehole collapsedue to borehole collapse
In fractured rocks, the membranes mayIn fractured rocks, the membranes may
get damaged if the membranes get stuckget damaged if the membranes get stuck
between the fissures.between the fissures.

28. Khalsa Heritage MemorialKhalsa Heritage Memorial
ComplexComplex
Anandpur SahibAnandpur Sahib
(The Ajooba Project)(The Ajooba Project)

29. MemorialMemorial –– A PerspectiveA Perspective
COMMEMORATING 300 YEARS OF KHALSA PANTH LAUNCHED BY GURU GOBIND SINGH

30. MemorialMemorial –– A PerspectiveA Perspective
Nishan-e-Khalsa
Complex C
Complex A
Complex B

31. Layout PlanLayout Plan

32. Site ConditionsSite Conditions
Anandpur SahibAnandpur Sahib -- on the bank of Riveron the bank of River
SutlejSutlej
Soils are Alluvial in natureSoils are Alluvial in nature
–– Foothills zone of HimalayasFoothills zone of Himalayas
StratigraphyStratigraphy
–– Sand mixed with pebbles / shingles withSand mixed with pebbles / shingles with
Intermediate clay layersIntermediate clay layers

33. View of the SiteView of the Site

34. Typical Soil ProfilesTypical Soil Profiles

35. Foundation AnalysisFoundation Analysis
Sufficient data of high quality - Greater Reliability of
the parameters
Analysis by four alternative methods:
SPT Values
Static Cone Penetration Test Results
Elastic Theory
Pressuremeter Test Results

36. Anandpur SahibAnandpur Sahib
Settlement Analysis by Various Approaches:
Foundation Size = 3m × 8m
Net Bearing Pressure = 30 T/m2
N Values SCPT Data Classical
Theory
Pressuremeter
33.6 mm 27.0 mm 31.3 mm 13.6 mm
Justify High Safe Bearing Pressures : 35~40 T/mJustify High Safe Bearing Pressures : 35~40 T/m22
for Settlements 15~35 mmfor Settlements 15~35 mm

37. Panipat RefineryPanipat Refinery

38. Panipat RefineryPanipat Refinery
Bore holesBore holes
–– SPT, Lab TestsSPT, Lab Tests
Static Cone Penetration TestsStatic Cone Penetration Tests
Pressuremeter TestsPressuremeter Tests

39. Design ProfileDesign Profile
Depth
(m)
Soil Classification
SPT (N)
Value
qc Value
kg/cm2
Limit
Pressure
Value
PL
(kg/cm2)
0 – 10 Clayey Silt / Sandy Silt 9 30 6.1
10 – 14 Clayey Silt / Sandy Silt 10 55 8.2
14 – 17 Clayey Silt / Sandy Silt 18 70 —
17 – 30
Silty Fine Sand / Fine
Sand
28 100 —

40. Open FoundationsOpen Foundations
Foundation
Depth (m)
Foundation
Width (m)
Net Allowable
Bearing
Pressure (T/m2)
Computed Settlement (mm)
Classical
Theory
SCPT
Profile
Pressure-
meter
Results
2.0 3.0 5.7 24.9 13.9 6.0
3.0 3.0 7.3 25.0 15.4 7.7

41. Pile FoundationsPile Foundations
Pile
Type
Pile dia.
(mm)
Pile
length
below
cut-off
level, m
Computed axial compressive capacity,
Tonnes
Using
c – φ
from
lab data
Using
inter-
preted
qu and φ
values
Using
SCPT
data
Using
pressure
-meter
data
Bored
Pile
500 18 75 76 138 124
Driven
Pile
500 21 95 104 184 171

43. KEYPLAN
RAJPURA
DTCCOLONY
UNIVERSITYCAMPUS
KHYBERPASS
CIVILLINES
KAMLANAGAR
JAWAHAR
MALKAGANJ
SABZIMANDIOLD
ROSHANARAGARDEN
HARIJAN
NAGAR
COLONY
DHAKACOLONY
GURUTEGBHADURNAGAR
YAMUNA RIVER
KOTLAFIROZ
I.G.INDOOR
RAJGHAT
SHANTI VANA
VIJAY
LALQILA
SADARBAZAR
SOUTHBLOCK
INDIA
STADIUM
PRAGATI
PANDARAPARK
SHAHFORT
MADIAN
GATE
NATIONAL
STADIUM
GHAT
PATELCHOWK
KM12
KM
17
KM10
KM
11
KM13
KM15
KM
16
KM18
KM19
KM20
KHYBERPASSDEPOT
RAILCORRIDOR
E-W
CORRIDOR
LEGEND:-
GPSSTATION GPS1
TRAVERSESTATION M1
CENTRELINEOFSTATION ISBT
KHYBERPASSDEPOTLINE
NORTH-SOUTHCORRIDOR
RAILCORRIDOR
EAST-WESTCORRIDOR
MC1BMC1A
KM
10.015(ENDOFCONTRACT)
VISHWAVIDYALAYA
CIVILLINES
DELHIMAIN
ISBT
CHAW
ARIBAZAR
CENTRALSECTT.
CONNAUGHTPLACE
OLDSECRETARIAT
PATELCHOWK
NEW
DELHI
RAFI MARG
I.P.COLLEGE
KHALSA
COLLEGE
Underground Rail CorridorUnderground Rail Corridor

44. Pump Out / Aquifer TestPump Out / Aquifer Test
Full Scale Pump Out TestFull Scale Pump Out Test
–– Determine hydraulic parametersDetermine hydraulic parameters
–– For Design and ConstructionFor Design and Construction
Dewatering schemeDewatering scheme
–– Deep excavations 15Deep excavations 15 –– 18 m for station areas18 m for station areas
–– GWT not to be lowered outside the area toGWT not to be lowered outside the area to
avoid subsidence of existing structuresavoid subsidence of existing structures
Model the testModel the test -- RequirementRequirement

45. FullFull--scale Pump Out Testsscale Pump Out Tests
Determine hydraulic Parameters:Determine hydraulic Parameters:
–– Draw downDraw down –– time relationshiptime relationship
–– Transmissivity of aquifer test sectionTransmissivity of aquifer test section
–– Hydraulic conductivity (Permeability)Hydraulic conductivity (Permeability)
–– Storage coefficientStorage coefficient
–– Specific capacitySpecific capacity
–– Well efficiencyWell efficiency
To use in various softwares / models of hydrogeology to analyze the
dewatering scheme

46. DefinitionsDefinitions
Hydraulic Conductivity (K) m/sec
Volume of water (m3) through unit section of soil (m2) in unit time
(s) under unit hydraulic gradient.
Transmissivity (T) m2/day (Productivity of an aquifer)
Water capacity which flows per unit length through an aquifer under
hydraulic gradient
T = K x b ( b = depth of aquifer)
Storage coefficient (%)
Volume of water it takes / releases per unit surface area of aquifer
under unit change of head.
Specific capacity
Discharge for unit time for unit draw down
c = Q / s

47. SubSub--Strata FormationsStrata Formations
AlluviumAlluvium
RockRock
AlluviumAlluvium--RockRock

48. Testing ProcedureTesting Procedure
Installation of PW & OWInstallation of PW & OW
–– Well Depths, selection of slotted / blankWell Depths, selection of slotted / blank
portions etc.portions etc.
Step draw down testStep draw down test –– SDD testSDD test
Constant discharge testConstant discharge test –– CD testCD test
Recuperation / Recovery testRecuperation / Recovery test

49. Pump WellPump Well –– AlluviumAlluvium

50. Pump Well InstallationPump Well Installation

51. Pump Well Installation DetailsPump Well Installation Details

52. Test in ProgressTest in Progress

53. Flow MeterFlow Meter

54. Step Draw Down TestStep Draw Down Test
Steps estimated on maximum yield of the wellSteps estimated on maximum yield of the well
based upon well development databased upon well development data
Discharge is increased in steps of 100 min.Discharge is increased in steps of 100 min.
Discharge level controlled by Control Valve andDischarge level controlled by Control Valve and
Flow MeterFlow Meter
PurposePurpose
–– To estimate discharge for CD test for response ofTo estimate discharge for CD test for response of
aquiferaquifer
–– To estimate well parametersTo estimate well parameters

55. Time vs. Step DrawTime vs. Step Draw--Down atDown at
Pump WellPump Well

56. Discharge vs. Step DrawDischarge vs. Step Draw--
DownDown

57. Specific Draw Down vs.Specific Draw Down vs.
DischargeDischarge

58. Constant Discharge TestConstant Discharge Test
Select constant discharge value to stress aquiferSelect constant discharge value to stress aquifer
for proper response from SDD testfor proper response from SDD test
Pump well continuously pumpedPump well continuously pumped -- Water levelWater level
recorded in PW and OW at regular intervalsrecorded in PW and OW at regular intervals
Test continues till near steady state / equilibriumTest continues till near steady state / equilibrium
conditioncondition
PurposePurpose
–– To obtain hydraulic characteristics of the aquiferTo obtain hydraulic characteristics of the aquifer
within the radius of influence of Pump wellwithin the radius of influence of Pump well

59. C.D. TestC.D. Test –– Typical ResultTypical Result
0.001
0.01
0.1
1
10
1 10 100 1000 10000
Time, min
Correcteddrawdownsc,m
3.86
Time vs. Corrected Draw Down at PWTime vs. Corrected Draw Down at PW

60. Recovery TestRecovery Test
After CD test is complete, Pump isAfter CD test is complete, Pump is
stoppedstopped
Allow water table to riseAllow water table to rise
Take Water level readings in sameTake Water level readings in same
sequence as for CD testsequence as for CD test
Test continues till water level rises up toTest continues till water level rises up to
static levelstatic level

61. AnalysisAnalysis
Bottom plugged with bottom blank casing portionBottom plugged with bottom blank casing portion
–– Assumes only radial flowAssumes only radial flow
Analysis AssumesAnalysis Assumes
–– Uniform homogeneous soil mass with uniformUniform homogeneous soil mass with uniform
propertiesproperties
–– Permeability of strata below Pump well Very lowPermeability of strata below Pump well Very low
As such analysis assumes fully penetrating wellAs such analysis assumes fully penetrating well
–– drawdown to be correcteddrawdown to be corrected
AnalysisAnalysis –– Various approachesVarious approaches
–– Theis MethodTheis Method
–– CooperCooper--Jacob MethodJacob Method

62. Aquifer ParametersAquifer Parameters
( )2
c
2
QW u
T (m day)
4 s
T
K (m sec)
b
4AT t u
S
r
=
π
=
=
2
c
s
Corrected Drawdown, s s
2b
= −
Theis MethodTheis MethodCooperCooper--Jacob MethodJacob Method
2
0
2
2.3 Q
T (m day)
4 s
T
K (m sec)
b
2.25T t
S
r
=
πΔ
=
=

63. AlluviumAlluvium--Rock FormationRock Formation
Rock at 15 M below G.L.Rock at 15 M below G.L.
GWT at 3.0 M depthGWT at 3.0 M depth
Excavation to 18~20 M depthExcavation to 18~20 M depth
Water to be pumped out from rock strataWater to be pumped out from rock strata
–– To study response in alluviumTo study response in alluvium
Rock formation highly fractured, weathered,Rock formation highly fractured, weathered,
boulders at interfaceboulders at interface
Wells redesigned to suit requirementsWells redesigned to suit requirements
–– PW sealed in soils & OW in rock layersPW sealed in soils & OW in rock layers

64. Pump Well : AlluviumPump Well : Alluvium--RockRock

65. Observation Well : AlluviumObservation Well : Alluvium--
RockRock

66. Summary of ResultsSummary of Results
Formation Method
Aquifer Parameters
Coefficient of
Permeability
from Packer
permeability
tests in
Boreholes
(cm/sec.)
Tav
(m2/day)
Kav
(cm/sec)
Sav
Alluvium Strata
(Delhi Silt)
Theis 65 3.5 × 10−3 5 × 10−3
7.0 × 10−5
Cooper-Jacob 71 4.0 × 10−3 4 × 10−3
Rock Strata in
Soil-Rock
Formation (Delhi
Quartzite)
Theis 385 2.0 × 10−2 8 × 10−3
1.7 × 10−3
Cooper-Jacob 420 2.2 × 10−2 9 × 10−3

67. Geophysical InvestigationsGeophysical Investigations
Electrical Resistivity TestElectrical Resistivity Test
River Chairala, NepalRiver Chairala, Nepal

68. ERT as Investigation ToolERT as Investigation Tool
FAST TRACK Projects on infrastructureFAST TRACK Projects on infrastructure ––
bridgesbridges
–– Preliminary assessmentPreliminary assessment
–– Detailed assessmentDetailed assessment
In bouldersIn boulders -- soil matrix cost & time savingsoil matrix cost & time saving
can be substantialcan be substantial
–– No. of bore holes can be reducedNo. of bore holes can be reduced
Used in conjunction with BH data toUsed in conjunction with BH data to
estimate stratigraphy & continuityestimate stratigraphy & continuity

69. Schematic of Resistivity TestSchematic of Resistivity Test
Soil Resistivity Unit
Current
Meter
Battery
Volt
Meter
WennerElectrode
Configuration
A M N B
GL GL
a a a
I1 I2
P2
P1
II11 and Iand I22 are current electrodesare current electrodes
PP11 and Pand P22 are potential electrodesare potential electrodes
For WennerFor Wenner
Configuration,Configuration,
ApparentApparent
Resistivity,Resistivity,
ρρaa = 2= 2ππaV/IaV/I

70. Inverse Slope MethodInverse Slope Method
Spacing/App.Resistivity,a/ρα
Slope = 1/ρ1
Slope = 1/ρ2
Slope = 1/ρ3
h1
h2
Electrode Spacing, a

71. InterpretationInterpretation
Data matching techniqueData matching technique
Interpreted stratigraphyInterpreted stratigraphy –– average over theaverage over the
spread investigatedspread investigated
Scatter of the data points on the “a versus a/Scatter of the data points on the “a versus a/ρρa
plot” needs careful interpretationplot” needs careful interpretation
If three points lie on a straight line, one can beIf three points lie on a straight line, one can be
fairly confident that the interpretation is correct.fairly confident that the interpretation is correct.
Resistivity ranges for the different soil typesResistivity ranges for the different soil types
overlapoverlap
Needs experience & judgment for interpretationNeeds experience & judgment for interpretation

72. True Resistivity for AnalysisTrue Resistivity for Analysis
True Resistivity,
ohm-m
Interpreted Stratigraphy
30 – 75 Sand and silty sand
10 – 50 Stiff clay and sandy silt
50 – 100 Sand with gravel/pebbles
> 100 Hard clay
> 200
Pebbles and boulders intermixed
with sand

73. Interpreted StratigraphyInterpreted Stratigraphy
River Chairala, NepalRiver Chairala, Nepal
True
Resistivity,
(ohm-m)
30
55
High
High
100
True
Resistivity,
(ohm-m)
30
55
High
High
100
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0 10 20 30 40 50
Electrode Spacing, a (m)
ElectrodeSpacing/ApparentResistivity,a/ρa
Interpreted
Stratigraphy
Interpreted
Stratigraphy
Silty Sand
Clayey Silt
Clayey Silt
Pebbles &
Boulders
intermixed
with Sand
Pebbles &
Boulders
intermixed
with Sand

74. Generalized Site StratigraphyGeneralized Site Stratigraphy
River CharailaRiver Charaila

75. AdvantagesAdvantages
Stratigraphy & thickness of various layersStratigraphy & thickness of various layers
Confirm continuity & depth of variousConfirm continuity & depth of various
layerslayers
No. of bore holes can be reducedNo. of bore holes can be reduced
–– Reduction in investigation Time & costReduction in investigation Time & cost

76. LimitationsLimitations
Knowledge of geology/stratigraphyKnowledge of geology/stratigraphy –– forfor
interpretationinterpretation
Steeply dipping or variable strataSteeply dipping or variable strata –– may result inmay result in
erratic interpretationerratic interpretation
Location under waterLocation under water –– test not possibletest not possible
Geotechnical parametersGeotechnical parameters -- c andc and φφ, density, etc., density, etc.
not obtainednot obtained
Not an alternative to bore holesNot an alternative to bore holes
Interpreted stratigraphy as guideInterpreted stratigraphy as guide –– may varymay vary
from actualfrom actual

77. Concluding RemarksConcluding Remarks
In situ testing provides realistic dataIn situ testing provides realistic data
Modern testsModern tests –– SCPT & PMT provideSCPT & PMT provide
superior datasuperior data
Geophysical testsGeophysical tests –– ERT useful inERT useful in
bouldary stratabouldary strata
Aquifer testAquifer test –– tool for dewatering schemetool for dewatering scheme
Selection of testsSelection of tests –– AN ARTAN ART

78. Concluding RemarksConcluding Remarks
The geotechnical engineer has to becomeThe geotechnical engineer has to become
one with the soul of the soilone with the soul of the soil
–– Be a part of the soil: have feel of the soilBe a part of the soil: have feel of the soil
–– Feel the stresses: deform along with itFeel the stresses: deform along with it
The solution to the problem will emergeThe solution to the problem will emerge
from the soil itselffrom the soil itself
Use modern inUse modern in--situ tests for higher factorsitu tests for higher factor
of reliabilityof reliability
Interpretation is AN ARTInterpretation is AN ART

79. Thank U!Thank U!

80. Interpreted StratigraphyInterpreted Stratigraphy
River Chairala, NepalRiver Chairala, Nepal
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0 10 20 30 40 50
Electrode Spacing, a (m)
ElectrodeSpacing/ApparentResistivity,a/ρa
True
Resistivity,
(ohm-m)
30
55
High
High
100
True
Resistivity,
(ohm-m)
30
55
High
High
100
Pebbles &
Boulders
intermixed
with Sand
Pebbles &
Boulders
intermixed
with Sand
Silty Sand
Clayey Silt
Clayey Silt
0
5
10
15
20
25
30
40
35

81. Interpreted StratigraphyInterpreted Stratigraphy
River Chairala, NepalRiver Chairala, Nepal