14.528 drilled deep foundations soil...

Revised 9/2012

14.528 DRILLED DEEP FOUNDATIONSSoil Exploration/Determination of Soil Properties

Slide 1 of 125

REQUIREMENTS FOR ALL SUCCESSFULDEEP FOUNDATION PROJECTS

1st Leg:Design

3rd Leg:Inspection

2nd Leg:Construction

Revised 9/2012


Slide 2 of 125

SELECTED REFERENCES YOU SHOULD HAVE IN YOUR LIBRARY

EPRI EL-6800Manual for Estimating

Soil Properties for Foundation Design

(Kulhawy & Mayne 1991)

Naval Facilities Command (NAVFAC)

Soil Mechanics(DM7.01, 1986)

FHWA Manual on Subsurface

Investigations(NHI-01-031, 2001)

FHWA Evaluation of Soil & Rock Properties(IF-02-034, 2002)

AVAILABLE ON COURSE WEBSITE!

Revised 9/2012


Slide 3 of 125

OBJECTIVES OF SUBSURFACE EXPLORATION

Three (3) General Objectives for Subsurface Exploration:

1. Define Soil and Rock Stratigraphy and Structure within Proposed Construction Zone of Influence.

2. Obtain Groundwater Data.- Level at Time of Testing.- Seasonal Fluctuations.

3. Determine Engineering Properties of Subsurface Materials for Use in Foundation Design.

- Collect samples for laboratory testing.- Determine insitu engineering properties.

Photograph courtesy of www.cmeco.com

Revised 9/2012


Slide 4 of 125

GENERAL SUBSURFACE INVESTIGATION METHODS

METHOD Abbrv. ASTM SAMPLING MAX. DEPTH (ft)

Hand Auger Borings HABD1452-07a

D4700-91(06)Yes Typ. 6 - 8

20 (w/difficulty)

Test/Excavation Pits TP None YesLimits of

equipment(Typ. 20 ft)

Soil Test Borings STBD420-98(03)D1452-07a

D4700-91(06)Yes

~ 300 ft(dependent of

various factors)

Green – Near Surface : Red – Near and Deep

D420-98(2003) Standard Guide to Site Characterization for Engineering, Design, and Construction Purposes

Revised 9/2012


Slide 5 of 125

HAND AUGER BORINGS (HAB)

Two Man OperationPhotograph courtesy of

http://cees.ou.edu/ugrad/reu/

Typical HAB Cross-SectionFigure courtesy of

WPC Engineering Inc.

• Requires Manual Labor.

• Typical Depths up to 6 to 8 ft.

• Standard Diameter: 3¼ in(Other Diameters Available).

• Allows for soil samples (disturbed) to be collected for classification and laboratory testing (if desired).

Revised 9/2012


Slide 6 of 125

TEST/EXCAVATION PITS (TP)• Requires Appropriate

Construction Equipment (e.g. backhoe).

• Typical Depths up to 20 ft (limited by equipment).

• Pit size determined by needs.

• Allows for soil samples (disturbed) to be collected for classification and laboratory testing (if desired).

• Allows for greater examination of insitu soils by geotechnical engineers and engineering technicians.

Photographs courtesy of www.ees1.lanl.gov, photos.orr.noaa.gov, & www.kerrville.org

Revised 9/2012


Slide 7 of 125

Failing Truck Mounted Rig CME750 All-Terrain Rig

SOIL TEST BORING (STB) RIGS

Photographs courtesy of FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


Slide 8 of 125

MoDOT Track Mounted Rig

SOIL TEST BORING (STB) RIGS

Water Boring from Barge for Bridge Crossing

Wireline Rig for Kaolin MinesMacon, GA


Revised 9/2012


Slide 9 of 125

• Continuous flight augers, added in 5-ft increments.

• Limited to non-caving soils and depths < 30 ft.

• Solid flight augers are removed prior to soil sampling, thus labor-intensive.

• Auger diameters from 4 in to 8 in.

• Front end has finger or fish-tail bit to loosen soil.

• Spoil collects around top of borehole.

SOIL TEST BORINGS (STB)Solid Flight Augers

Solid Auger and Drill BitText & Photographs courtesy of FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


Slide 10 of 125

SOIL TEST BORINGS (STB)Solid Flight Augers


Revised 9/2012


Slide 11 of 125

• Continuous hollow flight augers, added in 5 ft increments.

• Hollow stem augers allow soil sampling without removal.

• Act as temporary casing to stabilize borehole.

• Center stem and plug are inserted down the hollow center during boring advance.

• HSA range from about 6 to 12 inch O.D. with 3 to 8 inch I.D.

• HSA generally limited to depths < 100 ft.

• HSA should not be used in loose silts and sands below the GWT.

Truck-Mounted Rig with

Hollow-Stem Augers

SOIL TEST BORINGS (STB)Hollow Stem Augers (HSA)

Text & Photographs courtesy of FHWA NHI Course 132031 Subsurface Investigations

HSA outer and inner assemblywith stepwise

center bit

Revised 9/2012


Slide 12 of 125

• Rotary wash techniques are best for borings extending below GWT.

• Rotary wash can achieve great depths > 300+ ft.

• Drilling bits:– Drag bits for clays– Roller bits for sand

• In rotary wash method, borehole is stabilized using either temporary steel casing or drilling fluid.

• Fluids include water, bentonite or polymer slurry, foam, or Revert that are re-circulated in tub or reservoir at surface.

SOIL TEST BORINGS (STB)Rotary Wash Borings

Truck Rig conducting rotary wash boring


Revised 9/2012


Slide 13 of 125

SOIL TEST BORINGS (STB)Rotary Wash Borings

Schematic(Hvorslev 1948)


Revised 9/2012


Slide 14 of 125

• Bucket auger drills are used for obtaining large disturbed or undisturbed samples.

• Diameters range from 0.6 m (2 ft) to 1.2 m (4 ft).

• Increment of 0.3 m to 0.6 m depths (1 to 2 feet).

• Good for gravelly soils and cobbles.

• Same rigs used for constructing Drilled Shafts.

Setup of rig for Bucket Auger Boring(ASTM D4700)

SOIL TEST BORINGS (STB)Bucket Auger Borings

Text and Figure courtesy of FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


Slide 15 of 125

• Disturbed Sampling (Most Common)– Bulk samples (from auger cuttings or TP

excavations).– Bucket samples (borrow pits).– Drive samples (e.g. split-spoon).– Laboratory Tests: Grain size, Atterberg

Limits, Specific Gravity, Organic Content, Hydraulic Conductivity (coarse grained), Shear Strength (coarse grained).

• Partially Undisturbed (ASTM D1587)– Continuous Hydraulic Push.

• Undisturbed Sampling (ASTM D1587)– Push Tubes (e.g. Shelby, Piston, Laval)– Rotary & Push (e.g. Denison, Pitcher)– Block Samples– Laboratory Tests: Consolidation, Hydraulic

Conductivity (cohesive), Shear Strength (cohesive)

SOIL SAMPLING


Split Spoon Sampler

Thin Wall Samplers

Revised 9/2012


Slide 16 of 125

UNDISTURBED SAMPLESSampling Disturbance

PhotoelasticityStudies

Radiography (X-rays) of Tubes


Revised 9/2012


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INSITU TESTING METHODSMETHOD Abbrv. ASTM SAMPLING MAX. DEPTH (ft)

Dynamic ConePenetrometer

DCP D6951-03 Yes(via HAB)

6 – 8 Typ.20 (w/difficulty)

Standard Penetration Test SPT D1586-08a Yes > 300 ft

(dependent on boring method)

Cone Penetration Test CPTD3441-05 D5778-07

No > 300 ft(typically 100 – 150 ft max)

Flat Plate Dilatometer DMT D6635-01 No > 300 ft(typically 100 – 150 ft max)

Pressuremeter PMT D4719-07 Yes (via boring)

> 300 ft(dependent on boring)

Vane Shear Test VST D2573-08 Yes (via Boring)

> 300 ft(dependent on boring)

Green – Near Surface : Red – Near and Deep

Revised 9/2012


Slide 18 of 125

• Labor Intensive (Can be done with one person, better with two).

• Several types in use:- Scala (1956)

- Sowers (Sowers and Hedges, 1966) (Common in Southeast US)

- Dual Mass (Army COE)

• Mainly used for residential construction and pavement subgrade evaluations.

• Conducted in conjunction with HAB’s (therefore, soil samples can be collected).

• Depth limited by soil type. 6 – 8 ft typical, 20 ft maximum (if lucky).

DYNAMIC CONE PENETROMETER (DCP)

Figure courtesy of WPC Engineering Inc.

Revised 9/2012


Slide 19 of 125

INSITU TESTING METHODS

Figure courtesy of FHWA NHI Course 132031Subsurface Investigations

Revised 9/2012


Slide 20 of 125

• Very common test worldwide

• 1902 - Colonel Gow of Raymond Pile Co.

• Split-barrel sample driven in borehole.

• Conducted on 2½ to 5 ft depth intervals.

• ASTM D1586 guidelines

• Drop Hammer (140 lbs falling 30 inches)

• Three increments of 6 inches each; Sum last two increments = “SPT N value" (blows/ft)

• Correlations available with all types of soil engineering properties.

• Disturbed Soil Samples Collected

STANDARD PENETRATION TEST (SPT) (ASTM D1586-08a)

Text courtesy of FHWA NHI Course 132031 Subsurface Investigations

Marking of 6 inch Increments for SPT Test Photograph courtesy of physics.uwstout.edu

Revised 9/2012


Slide 21 of 125Figures courtesy of J. David Rogers, Ph.D., P.E., University of Missouri-Rolla & FHWA NHI Course 132031


Typical Setup

Split Spoon Dimensions (after ASTM D1586)

Revised 9/2012


Slide 22 of 125


Figure courtesy of FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


Slide 23 of 125Figure courtesy of http://www.civil.ubc.ca


Revised 9/2012


Slide 24 of 125

STANDARD PENETRATION TEST (SPT)Factors Affecting SPT (after Kulhawy & Mayne, 1990 & Table 8. FHWA IF-02-034 )

Cause Effects Influence on N Value

Inadequate Cleaning of Borehole SPT not made in insitu soil, soil trapped, recovery reduced Increases

Failure to Maintain Adequate Head in Borehole Bottom of borehole may become quick Decreases

Careless Measure of Drop Hammer Energy varies Increases

Hammer Weight Inaccurate Hammer Energy varies Inc. or Dec.

Hammer Strikes Drill Rod Collar Eccentrically Hammer Energy reduced Increases

Lack of Hammer Free (ungreased sleeves, stiff rope, more than 2 turns on cathead, incomplete release of drop, etc.) Hammer Energy reduced Increases

Sampler Driven Above Bottom of Casing Sampler driven in disturbed soil Inc. Greatly

Careless Blow Count Recording Inaccurate Results Inc. or Dec.

Use of Non-Standard Sampler Correlations with Std. Sampler Invalid Inc. or Dec.

Coarse Gravel or Cobbles in soil Sampler becomes clogged or impeded Increases

Use of Bent Drill Rods Inhibited transfer of energy to sampler Increases

Revised 9/2012


Slide 25 of 125

CARE & PRESERVATION OF SOIL SAMPLES• Mark and Log samples upon

retrieval (ID, type, number, depth, recovery, soil, moisture).

• Place jar samples in wood or cardboard box.

• Should be protected from extreme conditions (heat, freezing, drying).

• Sealed to minimize moisture loss• Packed and protected against

excessive vibrations and shock.

Text and Figures courtesy of FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


Slide 26 of 125

TEST RESULTS(i.e. BORING LOG)


Shows the following:

Soil Profile (determined from sampling and boring information) with respect to depth and/or elevation.

Groundwater Table (GWT).

SPT N Values.

Laboratory Test Results (if available).

Boring Log courtesy of WPC Engineering Inc.

ASTM D5434-09 Standard Guide for Field Logging of Subsurface Explorations of Soil and Rock

Revised 9/2012


Slide 27 of 125

• Electronic Steel Probes with 60° Apex Tip• Hydraulic Push at 20 mm/s• No Boring, No Samples, No Cuttings, No

Spoil• Continuous readings of stress, friction,

pressure• With Pore Pressure Measurements (CPTu)• With Shear Wave Measurements (SCPT)

CONE PENETRATION TEST (CPT) (ASTM D5778-07)


Revised 9/2012


Slide 28 of 125

CONE PENETRATION TEST (CPT) (ASTM D5778-07)

Figures courtesy of FHWA NHI Course 132031 Subsurface Investigations

Shear Wave Velocity (Vs)

qc

Vs

u2

fs

Penetration Porewater Pressure (U2)

Sleeve Friction (fs)

Cone Tip Resistance (qc)

Revised 9/2012


Slide 29 of 125

CONE PENETRATION TEST (CPT) RIGS

Figures courtesy of FHWA NHI Course 132031 Subsurface Investigations & WPC Engineering Inc.

Revised 9/2012


Slide 30 of 125

0 100 2000

4

8

12

16

20

24

28

32

36

40

44

48

52

56

60

64

68Dep

6.89

0 1 2 0 2 4 6 0 2 4 6

Very s tiff fine grained (9)C la yey s il t to s i l ty c lay (4)

C la ys , c lay to s i lty c lay (3)

C la yey s il t to s i l ty c lay (4)

Sil ty sand to sandy s il t ( 5)

Sil ty sand to sandy s il t ( 5)C la ys , c lay to s i lty c lay (3)



C la yey s il t to s i l ty c lay (4)C la ys , c lay to s i lty c lay (3)Sil ty sand to sandy s il t ( 5)

C le an sands to s il ty sands (6)



C la yey s il t to s i l ty c lay (4)

CONE PENETRATION TESTING (CPT) RESULTSqc fs uo, u2 FRSoil Profile

CPT Results courtesy of WPC Engineering Inc.

Revised 9/2012


Slide 31 of 125

CONE PENETRATION TESTING(CPT)

Factors Affecting CPT ResultsFigure 9-2. FHWA NHI Course 132031 Subsurface Investigations

qc

Vs

U2

fs

Revised 9/2012


Slide 32 of 125

• Direct push of stainless steel plate at 20-cm intervals; No borings; no cuttings.

• Introduced by Marchetti (1980).

• 18o angled blade

• Pneumatic inflation of flexible steel membrane using nitrogen gas

• Two pressure readings taken (A and B) within about 1 minute

FLAT PLATE DILATOMETER (DMT) (ASTM D6635-01(2007))

• B

• A

Figures and Text courtesy of FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


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Revised 9/2012


Slide 34 of 125

• Calibrations: A, B (positive values)• Readings: contact pressure "A" and

expansion pressure "B" with depth• Corrections for membrane stiffness in air:

p0 = 1.05(A + A) - 0.05(B - B)p1 = B -B

• DMT INDICES:• ID = material index = (p1-po)/(po-uo)• ED = dilatometer modulus = 34.7(p1-po)• KD = horizontal stress index

= (po-uo)/vo’


• B

• A

Text courtesy of FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


Slide 35 of 125

Marchetti Device (ASCE JGE, March 1980; ASTM Geot. Testing J., June 1986)

FLAT PLATE DILATOMETER (DMT) (ASTM D6635-01(2007))Manual Reading System (Standard)


Revised 9/2012


Slide 36 of 125

FLAT PLATE DILATOMETER (DMT) (ASTM D6635-01(2007))Computerized System (Standard)


Revised 9/2012


Slide 37 of 125

FLAT PLATE DILATOMETER (DMT) (ASTM D6635-01(2007))Results – Charleston, SC Project

Soil BehaviorClassification

ED with Depth

Raw Data & Calibrations

DMT Results courtesy of WPC Engineering Inc.

Revised 9/2012


Slide 38 of 125

0

2

4

6

8

10

12

14

160 200 400 600 800

Modulus ED (atm)

0

2

4

6

8

10

12

14

16

0 500 1000 1500

Pressure (kPa)

Dep

th (m

eter

s)

PoP1

0

2

4

6

8

10

12

14

16

0 1 10

Material Index ID

Clay Silt

0

2

4

6

8

10

12

14

16

0 5 10 15

Horiz. Index KD

FLAT PLATE DILATOMETER (DMT) (ASTM D6635-01(2007))Results - Piedmont Residuum, Charlotte, NC

DMT Results courtesy of FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


Slide 39 of 125

Also see Hajduk, E.L., Meng, J., Wright, W.B., and Zur, K.J. (2006). “DilatometerExperience in the Charleston, South Carolina Region”, 2nd International Conference onthe Flat Dilatometer, Washington, D.C.

SPT-CPT-DMT COMPARISON

From Local Project in

Charleston, SC Area (2000)

Revised 9/2012


Slide 40 of 125

PRESSUREMETER TEST (PMT) (ASTM D4719-07)


Revised 9/2012


Slide 41 of 125

0

1

2

3

4

5

0 100 200 300 400 500 600Volume Change (cc)

Pres

sure

(tsf

)

0

1

2

3

4

5

0 10 20 30 40 50 Creep (cc/min)

Pres

sure

(tsf

)

PRESSUREMETER (PMT) (ASTM D4719-07)Results – Utah DOT Project

PMT Results courtesy of FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


Slide 42 of 125

• Performed at bottom of boring or by direct push placement of device• Four-sided blade pushed into clays and silts to measure following:

suv (peak) = Peak Undrained Strength

suv (remolded) = Remolded Strength (after 10 revolutions)

Sensitivity, St = suv(peak)/suv

(remolded)

VANE SHEAR TEST (VST) (ASTM D2573-08)

Scandinavian Vanes

Pictures and text courtesy of FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


Slide 43 of 125

VANE SHEAR TEST (VST) (ASTM D2573-08)


Revised 9/2012


Slide 44 of 125

Dutch Vane Equipment, Holland VST in Upstate NY

VANE SHEAR TEST (VST) (ASTM D2573-08)Vane Shear Devices

Pictures courtesy of FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


Slide 45 of 125

0

5

10

15

20

25

30

0 10 20 30 40 50 60 70 80

Vane Strength, suv (kPa)

Dep

th (m

eter

s)

Peak

Remolded

0

5

10

15

20

25

30

0 1 2 3 4 5

Sensitivity, St

Dep

th (m

eter

s)

VANE SHEAR TEST (VST) (ASTM D2573-08)Results - San Francisco Bay Mud, MUNI Metro Station

VST Results courtesy of FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


Slide 46 of 125

INSITU TEST METHOD ADVANTAGES/DISADVANTAGES

Method Advantages Disadvantages

DCP • Quick• Low cost

• Limited depth range• Limited correlations of DCP values to soil properties.

SPT

• Obtain Sample + Number• Simple & rugged device at low cost• Suitable in many soil types• Can perform in weak rocks• Available throughout the U.S. and worldwide.• Many correlations with soil engineering properties exist

• Obtain Sample + Number• Disturbed sample (index tests only)• Crude number for analysis• Not applicable in soft clays and silts• High variability and uncertainty• Many correlations with soil engineering properties exist

Revised 9/2012


Slide 47 of 125



CPT

• Fast and continuous profiling of strata.• Economical and productive.• Results not operator-dependent.• Strong theoretical basis for interpretation.• Particularly suited to soft soils.

• High capital investment• Requires skilled operator for field use.• Electronics must be calibrated & protected.• No soil samples.• Unsuited to gravelly soils and cobbles.

DMT

• Simple and Robust Equipment.• Repeatable and Operator-Independent.• Quick and Economical.• Theoretical Derivations for elastic modulus, strength, stress history.

• Difficult to push in dense and hard materials.• Primarily established on correlative relationships.•Needs calibration for local geologies.

Revised 9/2012


Slide 48 of 125



VST

• Assessment of undrained shear strength of clays.• Simple test and equipment.• Measure inplace sensitivity.• Long history of use in practice, particularly embankments, foundations, & cuts.

• Limited to soft to stiff clays & silts with suv< 200 kPa• Slow & time-consuming• Raw suv needs empirical correction• Can be affected by sand seams and lenses

Revised 9/2012


Slide 49 of 125

• Geophysical Methods

• Geologic Mapping (need qualified geologists)

• Drilling and Coring

• Exploration Test Pits

ROCK EXPLORATION

UML Health and Social Sciences BuildingLowell, MA

June 14, 2011

Revised 9/2012


Slide 50 of 125

ROCK EXPLORATIONDrilling and Coring

Sinkhole in Limestone TerrainOrlando, FL

• STB Refusal– Auger refusal

– SPT refusal (> 50 blows per 1 inch penetration)

• Coring (ASTM D2113)• Noncore Drilling

• Percussive Methods


ASTM D2113-08 Standard Practice for Rock Core Drilling and Sampling of Rock for Site Investigation

Revised 9/2012


Slide 51 of 125

Air-Tracks Drilling for Dynamite Placement Penobscot, Maine

Photograph courtesy of FHWA NHI Course 132031Subsurface Investigations

ROCK EXPLORATIONPercussive Drilling

Revised 9/2012


Slide 52 of 125

ROCK EXPLORATIONDrilling – Rotary Wash

Tricone, Roller,Plug Bits Roller Bits

Drill Rig


Revised 9/2012


Slide 53 of 125

ROCK EXPLORATIONCoring

• Diamond Bits. Best and hardest, producing high quality core. Fastest cutting rates. Expensive.

• Synthetic Bits. Less expensive. Generally good quality cores.

• Tungsten Carbide Bits. Least expensive. Slower coring rates.

Photograph courtesy of www.ackerdrill.com

Carbide Type Bits

Diamond, Carbide Tungsten, SawtoothDiamond

Revised 9/2012


Slide 54 of 125

• Most rugged, least expensive.

• Consists of head section, core recovery tube, reamer shell, & cutting bit.

• Often used as starter when beginning core operations

ROCK EXPLORATIONCoring – Single Tube Core

Text & Figures courtesy of FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


Slide 55 of 125

• Double tube core barrel is the standard. • Outer barrel rotates with cutting bit.• Inner barrel is either fixed or swivel type

(with bearings) that retains core sample.• Core diameters generally range from 21

to 85 mm (0.85 to 3.35 inch).• NX core: standard diameter = 54 mm

(2.15 inches).• ASTM C42: The diameter of cores for

determining f’c in load bearing structural members shall be at least 3.70 in.

ROCK EXPLORATIONCoring – Double Tube Core


Outer Barrel Assembly

Inner Barrel Assembly

Revised 9/2012


Slide 56 of 125

• Good for obtaining core samples in fractured rock and highly weathered rocks.

• Outer core barrel for initial cut and second barrel to cut finer size. Third barrel to retain cored samples.

• Reduces frictional heat that may damage samples.

ROCK EXPLORATIONCoring – Triple Tube Core


Revised 9/2012


Slide 57 of 125Text & Figures courtesy of FHWA NHI Course 132031 Subsurface Investigations

• Rotary wash with water, foam, or drilling mud (bentonitic or polymeric slurries).

• Fluids reduce wear on drilling and coring bits by cooling.

• Fluids remove cuttings & rock flour.

• Re-circulate to filter fluids and to minimize impact on environment

ROCK EXPLORATIONCoring – Drilling Fluids Notes

Revised 9/2012



• Stabilizes boreholes• Driven casing • Drilled-in casing• Dual wall reverse circulation

method• Use in areas with expected

large losses in drilling fluid• Inner section for sampling• Outer casing maintains fluids

for drilling

ROCK EXPLORATIONCoring – Casing

Drilled-In Dual Wall

Revised 9/2012


Slide 59 of 125Figures courtesy of FHWA NHI Course 132031 Subsurface Investigations

ROCK EXPLORATIONCore Recovery

• Core Runs taken in either 5- or 10-foot sections.

• Log the amount of material recovered.

• Core Recovery is percentage retained.

• RQD (Rock Quality Designation) is a modified core recovery.

Revised 9/2012



ROCK EXPLORATIONCore Recovery

• Cores should be stored in either wooden boxes or corrugated cardboard box.

• Box marked with boring number, depth of core run, type core, bit type, core recovery (CR), rock type, RQD, and other notes.

• Core operations should be documented:• Loss of fluid• Drilling rates• Sudden drop in rods• Poor recovery• Loss of core

Revised 9/2012



ROCK EXPLORATIONCare & Preservation• Routine: Core boxes

• Special: Plastic sleeves• General: Avoid

exposure to shock and vibration during handling and transport.

• Non-natural fractures may result from excessive movements, temperatures, and exposure to air.

• Store for future reference

Revised 9/2012


Slide 62 of 125

GEOPHYSICAL METHODS – MECHANICAL WAVES

Crosshole Tests (CHT)(FHWA NHI-01-031 Figurer 5-25)

Seismic Refraction (SR)(courtesy of www.enviroscan.com)

Also Available:Downhole Tests (DHT)Spectral Analysis of Surface Waves (SASW)

Revised 9/2012


Slide 63 of 125

Ground Penetrating Radar (GPR)(photographs courtesy of http://www.geomodel.com)

GEOPHYSICAL METHODS – ELECTROMAGNETIC WAVES

Electrical Resistivity (ER) Survey Results(FHWA NHI-01-031 Figurer 5-35)

Other Methods:Magnetometer Surveys (MS)Resistivity Piezocone (RCPTu)

Electromagnetic (EM) Survey(FHWA NHI-01-031 Figurer 5-35)

Revised 9/2012


Slide 64 of 125

ADVANTAGES OF GEOPHYSICSNondestructive and/or non-invasive

Fast and economical testing Theoretical basis for interpretation

Applicable to soils and rocks

DISADVANTAGES OF GEOPHYSICSNo samples or direct physical penetration

Models assumed for interpretationAffected by cemented layers or inclusions.Results influenced by water, clay, & depth.

GEOPHYSICAL METHODS

GPR Results for UST(FHWA NHI-01-031 Figure 5-33)

MS Results for Oil Well Location(FHWA NHI-01-031 Figure 5-37)

Revised 9/2012


Slide 65 of 125

SUBSURFACE EXPLORATION PLANNINGSubsurface Exploration Plan:Function of

- Type and Critical Nature of Structure- Foundation Loads- Topographical Information- Site Geology (Soil and Rock Formations)- Location of Bedrock

• 1.5 m core to confirm• >3 m core required for foundations

on rock- Engineer’s Experience- Project Requirements

Consequences of Poor Subsurface Explorations

(photographs courtesy of NHI 13231)

USACE EM1110-1-1804“There are no hard and fast rules stating the

number and depth of samples for a particular geotechnical investigation.”

ASTM D420-98(2003) Standard Guide to Site Characterization for Engineering, Design, and Construction Purposes

Revised 9/2012


Slide 66 of 125

SUBSURFACE EXPLORATION PLANNINGIBC (2009) Section 1802.4.1The scope of the soil investigation including the number and types ofborings or soundings, the equipment used to drill and sample, the in-situ testing equipment and the laboratory testing program shall bedetermined by a registered design professional.

LET THE ENGINEERDECIDE!

Are Soil Explorations as Costly as the Repair?(Photographs courtesy of http://www.dot.state.co.us/geotech/geotechphotos.cfm)

YOU WILL NEED 1 BORING TO 100 ft TO DETERMINESEISMIC SITE CLASSIFICATION FOR IBC 2009

Revised 9/2012


Slide 67 of 125

The Massachusetts State Building Code

(7th Edition)780 CMR 1802.0 FOUNDATION AND

SOILS INVESTIGATIONS1802.5 Borings, Sampling and

Testing. The scope of the subsurface exploration, including the number and

types of borings, soundings or test pits, the equipment used to drill and sample, the in-situ testing equipment and the laboratory testing program,

shall be determined by a registered design professional.

LET THE ENGINEERDECIDE!

Photograph courtesy of TTU Center for Multidisciplinary Research in Transportation

(www.depts.ttu.edu/techmrtweb)

Revised 9/2012


Slide 68 of 125

SUBSURFACE EXPLORATION PLANNINGIBC (2009) Section 1803.3.1 (8th Edition of MSBC)The scope of the soil investigation including the number and types ofborings or soundings, the equipment used to drill and sample, the in-situ testing equipment and the laboratory testing program shall bedetermined by a registered design professional.

AGAIN,LET THE ENGINEER

DECIDE!

YOU WILL STILL NEED 1 BORING TO 100 ft TO DETERMINESEISMIC SITE CLASSIFICATION FOR IBC 2009

780 CMR (8th MSBC) Section 1803.2 Investigations Required.Exceptions: The building official shall be permitted to waive the requirement for a geotechnical investigation: 1. Where satisfactory data from adjacent areas is available that demonstrates an investigation is not necessary to meet the requirements of this chapter or,2. For unoccupied structures that do not pose a significant risk to public safety in the event of failure; or 3. For structures used for agricultural purposes.

Revised 9/2012


Slide 69 of 125

StructureFHWA

(NHI-01-031)USACE

(Table 2-4 EM1110-1-1804)NAVFAC

(DM7.01)

Min. # Spacing Min. # Spacing Min. # SpacingRigid Frame Structure 1 per 230m² 50 ft spacing

Low-Load Warehouse 4 @ Corners

Isolated Rigid Ftg < 2500ft² 2 @ O.C.

Isolated Rigid Ftg < 10,00ft² 3 around Per.

Houses – Subdivisions 1 per 8000m² 200 to 400 ft

Houses – Individual Lots 1 per lot

Bridge Piers1 (< 30m wide)2 (> 30m wide)

1

Retaining Walls 1 ≤ 60 m

Roads – 2 Lane ≤ 60 m 1 per 150 m @ CL

Roads – Multi Lane 1 per 75 m @ CL

Cuts and Embankments 1 ≤ 60 m

Culverts 1 60 to 120 m

Levees 6 to 12 m high 230 m100 to 200 ft

Levees 12 to 18 m high 150 m

SUBSURFACE TEST LAYOUT GUIDELINES

Revised 9/2012


Slide 70 of 125

SUBSURFACE TEST LAYOUT GUIDELINESSCDOT Geotechnical Design Manual (2010)

Foundation Type Min. Geotechnical Site Investigation ReferenceBridge Pile Foundation Minimum one testing location per bent1 Table 4-1

Bridge Single Foundation – Drilled Shaft Minimum one testing locations per foundation location Table 4-1

Bridge Multiple Foundation – Drilled Shaft2 Minimum two testing locations per bent location Table 4-1

Bridge Shallow Foundation – Founded on Soil Minimum three testing locations per bent location Table 4-1

Bridge Shallow Foundation – Founded on Rock Minimum two testing locations per bent location Table 4-1

Retaining Wall (within 150 of bridge abutment) Minimum one testing location at least every 75 ft Section 4.3.2

Retaining Wall (within 150 of bridge abutment) Minimum one testing location at least every 75 ft Section 4.3.2

Embankments Minimum one testing location at least every 500 ft Section 4.3.3

Cut Excavations Minimum one test locations every 300 ft along cut area Section 4.3.4

Culverts Minimum one testing locations @ each end of culvert and at every 100 ft of new crossline culvert2 Section 4.3.5

Sound Barrier Walls Dependant on shallow or deep foundation used2 Section 4.3.6

Misc. Structures (Light poles, overhead signs) Minimum of one test location per foundation location Section 4.3.7NOTES:

1. Spacing between testing locations may be increased, but shall be approved prior to field operations and shall include justification.Spacing may not exceed 100 ft.

2. See SCDOT Geotechnical Manual for additional details.

Revised 9/2012


Slide 71 of 125

Structure FHWA(NHI-01-031)

USACE(Table 2-4 EM111-1-1804)

Spread FootingsLf ≤ 2B, Min. Depth = 2B Min. Depth = 1½B

(4.5m for houses or to unweathered rock)

Lf ≥ 5B, Min. Depth = 4B

2B < Lf < 5B, Extrapolate

Deep Foundations (Soil)Min. Depth = 6m below

anticipated foundation tip elevation

Min. Depth = 1½B of imaginary footing @ 2/3

expected pile depthDeep Foundations (Rock) Min. Depth = 3m, 3D, or 2Bgroup

below foundation tip

Roadways Min. 2mMin. 3m below finished grade

(0.75m into rock)

Embankments/Culverts Min. 2x Embankment Height Height of Levee

Cuts Min. 5m below cut elevation

SUBSURFACE TEST DEPTH GUIDELINES

NOTE: B = Footing Width

Revised 9/2012


Slide 72 of 125

SUBSURFACE TEST DEPTH GUIDELINESSCDOT Geotechnical Design Manual (2010)

Foundation Type Minimum Depth Reference

Deep FoundationBorings shall extend below the anticipated pile or drilled shaft tip elevation a minimum of 20 ft or a minimum of 4 times the minimum pile group dimension, whichever is deeper.

Section 4.3.1

Bridge Shallow FoundationL ≤ 2B, Minimum test depth = 2BL ≥ 5B, Minimum test depth = 4B2B ≤ L ≤ 5B, Minimum test depth = 3B

Table 4-2

Retaining Walls At least 2X wall height beneath the anticipated bearing elevation or to auger refusal, whichever is shallower. Section 4.3.2

EmbankmentsAt least 2X embankment height beneath the anticipated bearing elevation (i.e. to a depth sufficient to characterize settlement and stability issues) or to auger refusal, whichever is shallower.

Section 4.3.3

Cut Excavations At least 25 feet below the anticipated bottom depth of the cut or to auger refusal, whichever is shallower. Section 4.3.4

CulvertsAt least 2X the embankment height beneath the anticipated bearing elevation or in accordance with the bridge spread footing criteria, whichever is deeper (or auger refusal)

Section 4.3.5

Sound Barrier Walls Dependant on shallow or deep foundation used1 Section 4.3.6

Misc. Structures (Light poles, overhead signs)

Same depth criteria as specified for the bridge test locations for the same type of foundation. Section 4.3.7

NOTES:1. See SCDOT Geotechnical Manual for additional details.

Revised 9/2012


Slide 73 of 125

TEST LOCATION PLAN (EXAMPLE)

Test Location Plan Example(Courtesy of WPC Inc.)

Scale

Shows test locations relative to site

Symbol key differentiates between test types

Project Information

Other Useful Data:- North Arrow- Topographic Information

Revised 9/2012


Slide 74 of 125

SUBSURFACE TEST LAYOUT & DEPTH GUIDELINESOther Guidelines

HUD Directive 4460.1 Rev 2 (1995)Shallow Foundations: 1 boring per 2,500 ft² Deep Foundations: 1 boring per 1,600 ft²

Borings must be at least to the bottom of proposed footings and deep enough to locatebearing strata that will support the proposed structure. When rock is encountered, depth ofdrilling into rock shall be at least 5 feet or enough to establish rock quality regarding voids,fissures and strength, or whether it is a boulder.

Hospital and Office Buildings (Sowers and Sowers, 1970)Boring Depth = 3(Number of Stories)0.7 (for light steel or narrow concrete buildings)Boring Depth = 6(Number of Stories)0.7 (for heavy steel or wide concrete buildings)

Revised 9/2012


Slide 75 of 125

SUBSURFACE TEST LAYOUT & DEPTH GUIDELINESOther Guidelines

ASCE (1972)

1. Determine for planned foundation.

2. Determine 'o with Depth.3. Determine Depth D1 at which =

0.1q (q = applied footing load)4. Determine Depth D2 at which

'o = 0.055. Minimum Depth is the smaller of

D1 and D2.

Figure 10.1. Das FGE (2005)

Revised 9/2012


Slide 76 of 125

From Paul W. Mayne, PhD, P.E., Professor, Civil Engineering, GT

DATA COLLECTION, INTERPRETATION, & ANALYSIS TO GEOTECHNICAL SOLUTIONS FLOW CHART

PRIOR INFORMATION• Reconnaissance• Topography• Geology• Hydrology• Environment

SITE EXPLORATION• Geophysics• Drilling and Coring• Sampling• In-situ Testing

LABORATORY TESTING• Index Properties• Strength• Stiffness/Compressibility• Flow/Permeability

INTERPRETED SOIL PARAMETERS

• Geostatic Stress State• Strength: Drained &

Undrained Cases• Stiffness & Rate Effects• Anisotropy, Dynamic

Response, Rheology

THEORETICAL EVALUATIONS

• Constitutive Models• Numerical Simulation• Analytical Solutions

PRIOR EXPERIENCE

• Statistical Trends• Empirical Correlations

ENGINEERING ANALYSIS

• Judgment• Hand Calculations• Computer Simulations• Chart Solutions• Experience

ANALYTICAL METHODS

• Elastic Theory• Theorem of Plasticity• Limit Equilibrium

GEOTECHNICAL SOLUTION• Safe• Feasible• Economical

NUMERICAL METHODS

• Finite Elements• Boundary Elements• Discrete Elements• Finite Difference

COLOR CODE:Blue: 14.330 & 14.333Red: 14.431

Revised 9/2012


Slide 77 of 125

N

DR = relative densityT = unit weightLI = liquefaction index' = friction anglec' = cohesion intercepteo = void ratioqa = bearing capacityp' = preconsolidationVs = shear waveE' = Young's modulus = dilatancy angleqb = pile end bearingfs = pile skin frictionSAND

cu = undrained strengthT = unit weightIR = rigidity index' = friction angleOCR = overconsolidationK0 = lateral stress stateeo = void ratioVs = shear waveE' = Young's modulusCc = compression indexqb = pile end bearingfs = pile skin frictionk = permeabilityqa = bearing stress

CLAY

STANDARD PENETRATION TEST

Courtesy of FHWA NHI Course 132031 Subsurface Investigations

What Do We Need? How Do We Get It?

Revised 9/2012


Slide 78 of 125

CORRECTIONS TO SPT N VALUENmeasured = Raw SPT Value from Field Test (ASTM D1586-08a)

N60 = Corrected N values corresponding to 60% Energy Efficiency(i.e. The Energy Ratio (ER) = 60% (ASTM D4633-10)

Note: 30% < ER < 100% with average ER = 60% in the U.S.

Factor Term Equipment Variable Correction

Energy Ratio CE = ER/60Donut HammerSafety Hammer

Automatic Hammer

0.5 to 1.00.7 to 1.20.8 to 1.5

Borehole Diameter CB

65 – 155 mm150 mm200 mm

1.001.051.15

Sampling Method CSStandard Sampler

Non-Standard Sampler1.0

1.1 to 1.3

Rod Length CR

3 – 4 m4 – 6 m6 – 10 m> 10 m

0.750.850.951.00

N60 = CECBCSCRNmeasured

For Guidance Only. Actual ER values should be measured per ASTM D4633

SPT CorrectionsFrom Table 9

FHWA IF-02-034

Revised 9/2012


Slide 79 of 125

Data from Robertson, et al. (1983), Courtesy of FHWA NHI Course 132031 Subsurface Investigations

CORRECTIONS TO SPT N VALUEEXAMPLE OF DATA FROM SAME SITE

4

6

8

10

12

14

16

0 10 20 30 40 50

Measured N-values

Dep

th (m

eter

s)

Donut

Safety

Sequence

ER = 34 (energy ratio)

45

40

41

41

39

47

56

5560

5663

63

63

64

69

4

6

8

10

12

14

16

0 10 20 30 40 50

Corrected N60

Dep

th (m

eter

s)

Donut

Safety

Trend

Revised 9/2012


Slide 80 of 125

Courtesy of FHWA NHI Course 132031 Subsurface

Investigations

EQUIVALENT ELASTIC MODULUS

Revised 9/2012


Slide 81 of 125

EQUIVALENT ELASTIC MODULUS WITH STRAIN LEVEL

Revised 9/2012


Slide 82 of 125

NORMALIZED SPT N VALUE (N1)60

(N1)60 = N60 values normalized to 1 atmosphere overburden stress.

(N1)60 = CNN60

Where:CN = (Pa/'vo)n

Pa = Atmospheric Pressure (1 atm = 14.7 psi = 2116 psf = 1.06 tsf)'vo = Insitu Vertical Effective Stressn = 1 (clays) and 0.5 to 0.6 (sands)

Revised 9/2012


Slide 83 of 125

CORRECTIONS TO CPT MEASUREMENTS (WITH U2)

Need to correct tip resistance (qc) for pore

pressure @ U2 location.

qc → qt

U2 = UbPore Pressure

Measurement behind Tip

Porous Element for U2Materials: Sintered Metals, Ceramics, Plastics (disposable)Saturation of Porous Elements: Water, Glycerine, SiliconeProcedures: Vacuum for 24-hours, Pre-Saturated Elements, Prophylactic to maintain fluids

Courtesy of FHWA IF-02-034

Revised 9/2012


Slide 84 of 125

WHAT DO WE NEED FOR GEOTECHNICAL DESIGN?1. Geostratigraphy:

- Layering- Soil Types- Depth to Strata

2. Total and Effective Soil Stresses:- Soil Unit Weight ( or sat = t)- GWT Location (u)

3. Shear Strength:- Effective Friction Angle (')- Effective Cohesion Intercept (c')- Undrained Shear Strength (Su)

4. Stress State:- Maximum Past Pressure (’vm).- Overconsolidation Ratio (OCR)- Coefficient of Earth Pressure at Rest (Ko)

5. Stiffness and Moduli:- Elastic Modulus (E)- Shear Modulus (G)- Compression Index (Cc)

6. Consistency:- Void Ratio (e)- Relative Density (Dr)

7. Flow Parameters:- Coefficient of Permeability (k)- Coefficient of Consolidation (cv, ch)

Revised 9/2012


Slide 85 of 125

INSITU TESTS – APPLICABLE SOIL PROPERTIESSoil Property SPT CPT DMT

Soil Classification USCS Behavior BehaviorGroundwater Table Yes Yes Possible

Effective Friction Angle (') (Sands) Yes Yes YesRelative Density (Dr) (Sands) Yes Yes Yes

Unit Weight () Yes Yes YesUndrained Shear Strength (Su) Possible1 Yes Yes

Maximum Past Pressure ('vm or 'p) Possible1 Yes Yes

Overconsolidation Ratio (OCR) Yes

Shear Wave Velocity (Vs) Yes (SCPTu) Yes (SDMT)

Small Strain Shear Modulus (Gmax) Yes (SCPTu) Yes (SDMT)

Small Strain Young’s Modulus (Emax) Yes (SCPTu) Yes (SDMT)

E (Young’s Modulus) Possible1 Possible1 Yes

Coefficient of At-Rest Earth Pressure (Ko) Yes Yes

IBC Site Classification Yes (N) Yes (Vs, Su) Yes (Su)

NOTES:1. Possible, but not recommended for use.

After Table 10. FHWA IF-02-034

Revised 9/2012


Slide 86 of 125

COEFFICIENT OF VARIATION (V) FOR GEOTECHICAL PROPERTIES AND INSITU TESTS (after Duncan, 2000)

Measured or Interpreted Parameter

V(%)

Unit Weight () 3 to 7

Effective Friction Angle (') 2 to 13

Undrained Shear Strength (Su) 13 to 40

Undrained Shear Ratio (Su/'vo) 5 to 15

SPT N Value 15 to 45

Electric CPT Tip Resistance (qt) 5 to 15

Also see Chapter 8 – Applying Judgment in Selecting Soil and Rock Properties for Design (FHWA IF-02-034).

Coefficient of Variation: A measure of dispersion of a probability distribution.

after Table 52. FHWA IF-02-034

Revised 9/2012


Slide 87 of 125

SOIL BORINGS – DETERMINATION OF SOIL STRATIGRAPHY

Figure 9-1. FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


Slide 88 of 125

CONE PENETRATION TEST (CPT)DETERMINATION OF SOIL STRATIGRAPHY

CPT Soil Behavior Classification(Based on qt, FR or Bq)


Revised 9/2012


Slide 89 of 125

CONE PENETRATION TEST (CPT)DETERMINATION OF SOIL STRATIGRAPHY

Revised 9/2012


Slide 90 of 125

0 100 2000

4

8

12

16

20

24

28

32

36

40

44

48

52

56

60

64

68Dep

6.89

0 1 2 0 2 4 6 0 2 4 6

Very stiff fine grained (9)C la yey s il t to s ilty c lay (4)

C la ys , c lay to s il ty c lay (3)

C la yey s il t to s ilty c lay (4)

Si lty sand to sandy s ilt (5)

Si lty sand to sandy s ilt (5)C la ys , c lay to s il ty c lay (3)



C la yey s il t to s ilty c lay (4)C la ys , c lay to s il ty c lay (3)Si lty sand to sandy s ilt (5)

C le an sands to s il ty sands (6)



C la yey s il t to s ilty c lay (4)

CONE PENETRATION TESTING (CPT) RESULTSqc fs uo, u2 FRSoil Profile

CPT Results courtesy of WPC Engineering Inc.

LAYER 1

LAYER 2

LAYER 3LAYER 4

LAYER 5

LAYER 6

LAYER 8

LAYER 7

Revised 9/2012


Slide 91 of 125

00

01,upppIIndexMaterial D

p0

p10.1 1 10

Material Index (ID)

0.6 1.8

Clay Silt Sand

FLAT PLATE DILATOMETERDETERMINATION OF SUBSURFACE DATA


Revised 9/2012


Slide 92 of 125

FLAT PLATE DILATOMETERDETERMINATION OF SUBSURFACE DATA

Figure 43. FHWA IF-02-034

Revised 9/2012


Slide 93 of 125

SOIL PROFILE (EXAMPLE)

Plan View(Boring Locations)

Soil Profile(Cross-Section)

Figure courtesy of FHWA

Revised 9/2012


Slide 94 of 125


Boring Location PlanFigure 45. FHWA IF-02-034

Revised 9/2012


Slide 95 of 125


Figure 46. FHWA IF-02-034

Soil Profile

Revised 9/2012


Slide 96 of 125

Triaxial Database from Frozen Sand Samples

20

25

30

35

40

45

50

55

0 10 20 30 40 50 60Normalized (N1)60

Frict

ion

Ang

le,

' (de

g)

Sand (SP and SP-SM)

Sand Fill (SP to SM)

SM (Piedmont)

H&T (1996)

' = [15.4(N1)60]0.5+20

EFFECTIVE FRICTION ANGLE (') FOR SANDS - SPT


Revised 9/2012


Slide 97 of 125

0

10

20

30

40

50

60

25 30 35 40 45 50

Effective Friction Angle, ' (deg)

Dep

th (fe

et) SPT-N

Triaxial

EFFECTIVE FRICTION ANGLE (') FOR SANDS - SPTComparison of ' from SPT and Laboratory Tests

Peidmont Residuum (GT Campus) – Silty Sand (SM)

Courtesy FHWA NHI Course 132031 Subsurface Investigations

0

10

20

30

40

50

60

0 10 20 30 40 50

SPT N-values (bpf)

Dep

th (fe

et)

Revised 9/2012


Slide 98 of 125

25

30

35

40

45

50

55

10 100 1000Normalized Tip Stress, qt/vo'

Frict

ion

Ang

le, '

(de

g)

Frankston Sand

Ticino Sand

Edgar Sand

Hokksund Sand

Lone Star Sand

R&C (1983)

' = arctan[0.1 + 0.38 log (qt/vo')]

EFFECTIVE FRICTION ANGLE (') FOR SANDS - CPT


Revised 9/2012


Slide 100 of 125

SOIL SHEAR STRENGTH CORRELATIONSFROM INSITU TESTING

Shear Strength

Parameter

Insitu Testing Method

SPT CPT DMT

Effective Soil Friction

Angle (′)

See Slide 24 arctan[0.1+0.38log(qt/′vo)] 28°+14.6°log(KD)-2.1°log2KD

See Slide 24 Robertson and Campanella(1983)

Marchetti et al. (2001)ISSMGE TC 16 Report

Undrained Shear

Strength (Su)

NO ACCEPTABLE CORRELATIONS

(qt-vo)/Nkt(Nkt = 15 for CHS) 0.22′vo(0.5KD)1.25

Aas et al. (1986) Marchetti et al. (2001)ISSMGE TC 16 Report

NOTES:1. (N1)60 = N60(Pa/′vo)0.5 for sands. Pa = Atmospheric Pressure = 1 bar ≈ 1 tsf.2. ′vo = Insitu Effective Overburden Pressure = Insitu Vertical Effective Stress.3. vo = Total Overburden Pressure = Insitu Vertical Total Stress.

Revised 9/2012


Slide 101 of 125

SOIL SHEAR STRENGTH CORRELATIONSFROM INSITU TESTING

Equation Reference

' = 54° - 27.6034*exp(-0.014(N1)60)

Peck, Hanson, & Thorton (1974) from Kulhawy & Mayne (1990)

' = [20*(N1)60]0.5 + 20°for 3.5 (N1)60 30

Hatanaka & Uchida (1996)

' = 27.1° +0.3*(N1)60 –0.00054(N1)2

60

Peck, Hanson, & Thorton (1974)

from Wolff (1989)

' = [15.4(N1)60]0.5 + 20°Mayne et a. (2001)

based on Hatanaka &

Uchida (1996)

' = [15(N1)60]0.5 + 15°for (N1)60 > 5 and 45°

JRA (1996)

Effective Soil Friction Angle (′) summary from NCHRP Report 651 (2010)

Revised 9/2012


Slide 102 of 125

after Fang et al. (1991) and EM 1110-1-1905.NOTE: 1 MPa = 10.44 tsf

Soil Density/Consistency N qt(MPa)

t(pcf)

′(°)

SANDS

V. Loose 0-4 0-2 90-105 <30

Loose 5-10 2-5 95-110 30-35

Medium Dense 11-30 5-15 105-120 35-38

Dense 31-50 15-25 115-130 38-41

Very Dense >50 >25 125-140 41-44

COHESIVE SOILS

Very Soft 0-2 0-0.5 90-100

NA

Firm 2-8 0.5-1.5 90-110

Stiff 9-15 1.5-3 105-125

Very Stiff 15-30 3-6 115-135

Hard >30 >6 120-140

SOIL ENGINEERING PROPERTY CORRELATIONSFROM INSITU TESTING (TABLE 1)

Revised 9/2012


Slide 103 of 125

SOIL ENGINEERING PROPERTIES DETERMINATIONMaximum Allowable Shear Strengths (SCDOT, 2010)

Cannot be exceeded with laboratory testingAND

written permission from SCDOT

Revised 9/2012


Slide 104 of 125

SOIL ENGINEERING PROPERTIES DETERMINATIONMaximum Allowable Shear Strengths (SCDOT, 2010)

Cannot be exceeded with laboratory testingAND

written permission from SCDOT

Revised 9/2012


Slide 105 of 125

EXAMPLE INTERPRETATION –

SPT Given Data

Provided:- Soil Stratigraphy- USCS Classification- Groundwater Table(@ Time of Testing)

- SPT N Values(No Energy Measurements)

- Drilling Method (HSA)- Date Started/Ended

Revised 9/2012


Slide 106 of 125t from Table 1 (Lecture Notes)

EXAMPLE INTERPRETATION – SPTDetermination of Nave, t, and 'vo

0 1000 2000'vo (psf)

25

20

15

10

5

0

Dept

h (f

t)

0

460

9201030

14801565

0 10 20 30B-7 N (bpf)

25

20

15

10

5

0

Dep

th (f

t)

SAND - Silty SANDNave = 17

use t = 115 pcf

Sandy SILTNave = 4

use t = 110 pcf

Clayey SILT (MH)/MARLNave = 4

use t = 115 pcf

Revised 9/2012


Slide 107 of 125

Calculate Nave for sand layer from 0 to 8 ft.

Simple Way:Using Table 1 (Lecture Notes)

Nave = 17, therefore ' ≈ 36°

Formula Way:Use Mayne et al. (2001)

' = [15.4(N1)60]0.5 + 20° and (N1)60 = N60(Pa/'vo)0.5

Use Nave = 17, 'vo,ave = 460 psf, and Pa = 2115 psfTherefore, (N1)60 = 17(2115/460)0.5 = 36

Using equation ' = [15.4(N1)60]0.5 + 20°, ' = 44°

USE ' = 36°

EXAMPLE INTERPRETATION – SPTDetermination of Effective Friction Angle (')

0 10 20 30B-7 N (bpf)

25

20

15

10

5

0

Dep

th (f

t)


use t = 115 pcf

Sandy SILTNave = 4

use t = 110 pcf


use t = 115 pcf

Revised 9/2012


Slide 108 of 125

qt (tsf) fs (tsf) Uo, U2 (tsf) FRSoil Profile

EXAMPLE INTERPRETATION – CPT Given DataD

epth

(ft)

Revised 9/2012


Slide 109 of 125

qt (tsf) fs (tsf) Uo, U2 (tsf) FRSoil ProfileEXAMPLE INTERPRETATION – CPT Soil Layers

7ft

Dep

th (f

t)

17ft

GWT @ 9ft

SAND

SANDY SILT

SILTY CLAY(MARL)

Revised 9/2012


Slide 110 of 125

EXAMPLE INTERPRETATION – CPTDetermination of qt,ave, t, and 'vo

0 1000 2000'vo (psf)

25

20

15

10

5

0

Dep

th (f

t)

0

405

8051025

1170

1405

1590

1775

t from Table 1 (Lecture Notes)

0 100 200 300C-7 qt (tsf)

25

20

15

10

5

0

Dep

th (f

t)

SAND - Silty SANDqt,ave 125 tsf

use t = 115 pcf

Sandy SILTqt,ave 22 tsf

use t = 110 pcf

Silty CLAY - CLAYqt,ave 26 tsf

use t = 115 pcf

Revised 9/2012


Slide 111 of 125

EXAMPLE INTERPRETATION – CPTDetermination of Effective Friction Angle (')

Calculate qt,ave for sand layer from 0 to 7 ft

Simple Way:Using Table 1 (Lecture Notes)

qt,ave ≈ 125 tsf ≈ 12 MPatherefore ' ≈ 37°

Formula Way:Using Robertson and Campanella (1983) formula.

' = arctan[0.1+0.38log(qt/ 'vo)]

Use qt,ave ≈ 12 MPa (250000 psf) & 'vo,ave = 405 psf for layer.Using equation, ' = 49°

USE ' ≈ 37°0 100 200 300

C-7 qt (tsf)

25

20

15

10

5

0

Dep

th (f

t)


use t = 115 pcf


use t = 110 pcf


use t = 115 pcf

Revised 9/2012


Slide 112 of 125

EXAMPLE INTERPRETATION – CPTDetermination of Undrained Shear Strength (Su)

Calculate qt,ave for Sandy Silt from 7 to 17 ftCalculate qt,ave for Silty Clay from 17 to 24 ft

Formula Way:use Aas et al. (1986)

Su = (qt-vo)/NktNkt = 15 for CHS (Lecture Slides)

Sandy SILT LayerUse qt,ave ≈ 22 tsf & vo,ave = 1355 psfSu = 2850 psf

Silty CLAY LayerUse qt,ave ≈ 26 tsf & vo,ave = 2310 psfSu = 3300 psf0 100 200 300

C-7 qt (tsf)

25

20

15

10

5

0

Dep

th (f

t)


use t = 115 pcf


use t = 110 pcf


use t = 115 pcf

Revised 9/2012


Slide 113 of 125

EXAMPLE INTERPRETATION – SPT & CPTComparison of Soil Engineering Properties

SPT CPT

Two Tests ~ 15 ft Apart

Method t(pcf)

'(°)

SPT - Table 1 115 36

SPT - Formula NA 44

CPT - Table 1 115 37

CPT - Formula NA 49

Sand Layer Properties

0 10 20 30B-7 N (bpf)

25

20

15

10

5

0

Dep

th (f

t)


use t = 115 pcf

Sandy SILTNave = 4

use t = 110 pcf


use t = 115 pcf

0 100 200 300C-7 qt (tsf)

25

20

15

10

5

0

Dept

h (ft

)


use t = 115 pcf


use t = 110 pcf


use t = 115 pcf

Revised 9/2012


Slide 114 of 125

INDEX PROPERTIES OF INTACT ROCK• Specific Gravity of Solids (Gs)

• Unit Weight ()• Porosity (n)• Ultrasonic Velocities (Vp and Vs)• Compressive Strength (qu)• Tensile Strength (T0)• Elastic Modulus, ER (at 50% of qu)


Revised 9/2012


Slide 115 of 125

SPECIFIC GRAVITY OF ROCK MINERALS

0 1 2 3 4 5 6 7 8

Specific Gravity of Solids, Gs

halitegypsum

serpentinequartz

feldsparchloritecalcite

dolomiteolivinebaritepyrite

galena

Speci f i c G rav i t i es of Rock Mi

Reference Value(fresh water)

Common MineralsAverage Gs = 2.70


Revised 9/2012


Slide 116 of 125

UNIT WEIGHTS OF ROCKS

14

16

18

20

22

24

26

28

0.0 0.1 0.2 0.3 0.4 0.5 0.6

Porosity, n

Satu

rate

d Unit

Weigh

t,

T (kN

/m3 )

Dolostone GraniteGraywacke LimestoneMudstone SiltstoneSandstone Tuff

sat =water [ Gs(1-n) + n]

Gs = 2.80 2.65 2.50


Revised 9/2012


Slide 117 of 125

ULTRASONIC VELOCITIES OF ROCKSSeismic Velocities for Intact Rock Materials

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

Compression Wave, Vp (m/s)

Shea

r W

ave,

Vs (m

/s)

Limestone Chalk Marble SchistTuff Slate Anhydrite GrandioriteDiorite Gabbro Granite DuniteBasalt Dolostone Mudstone Siltstone


Revised 9/2012


Slide 118 of 125

STRENGTH OF INTACT ROCKS

• Compressive Strength, u = qu

• (Direct) Tensile Strength, *T0

• (Indirect) Brazilian Strength, T0

• Shear Strength,

– Across the intact rock

– Along the planar surface (joints)Courtesy of FHWA NHI Course 132031 Subsurface Investigations

Revised 9/2012


Slide 119 of 125

LAB DATA ON INTACT ROCKS (GOODMAN, 1989) qu T0 ER Ratio Ratio

Intact Rock Material (MPa) (MPa) (MPa) (-) qu/T0 ER//qu

Baraboo Quartzite 320.0 11.0 88320 0.11 29.1 276Bedford Limestone 51.0 1.6 28509 0.29 32.3 559Berea Sandstone 73.8 1.2 19262 0.38 63.0 261Cedar City Tonalite 101.5 6.4 19184 0.17 15.9 189Cherokee Marble 66.9 1.8 55795 0.25 37.4 834Dworshak Dam Gneiss 162.0 6.9 53622 0.34 23.5 331Flaming Gorge Shale 35.2 0.2 5526 0.25 167.6 157Hackensack Siltstone 122.7 3.0 29571 0.22 41.5 241John Day Basalt 355.0 14.5 83780 0.29 24.5 236Lockport Dolomite 90.3 3.0 51020 0.34 29.8 565Micaceous Shale 75.2 2.1 11130 0.29 36.3 148Navajo Sandstone 214.0 8.1 39162 0.46 26.3 183Nevada Basalt 148.0 13.1 34928 0.32 11.3 236Nevada Granite 141.1 11.7 73795 0.22 12.1 523Nevada Tuf f 11.3 1.1 3649.9 0.29 10.0 323Oneota Dolomite 86.9 4.4 43885 0.34 19.7 505Palisades Diabase 241.0 11.4 81699 0.28 21.1 339Pikes Peak Granite 226.0 11.9 70512 0.18 19.0 312Quartz Mica Schist 55.2 0.5 20700 0.31 100.4 375Solenhofen Limestone 245.0 4.0 63700 0.29 61.3 260Taconic Marble 62.0 1.2 47926 0.40 53.0 773Tavernalle Limestone 97.9 3.9 55803 0.30 25.0 570

Statistical Results: Mean = 135.5 5.6 44613 0.29 39.1 372.5S.Dev. = 93.7 4.7 25716 0.08 35.6 193.8

Note: 1 MPa = 10.45 tsf = 145.1 psi


Revised 9/2012


Slide 120 of 125

CLASSIFICATION FOR ROCK MATERIAL STRENGTH


Revised 9/2012


Slide 121 of 125

ROCK MASS CLASSIFICATIONS• RQD - Early form of rating rock mass

• Geomechanics System - Rock Mass Rating (RMR) by Bieniawski (1984, 1989)

• Q-System - Norwegian Geotechnical Institute (Barton, et al. 1974)

• Geological Strength Index, GSI (Hoek, et al., 1995)


Revised 9/2012



ROCK QUALITY DESCRIPTION(RQD)

• The RQD is a modified core recovery.

• Measure of the degree of fractures, joints, and discontinuities of rock mass

• RQD = sum of pieces > 100 mm (4 inches) divided by total core run.

• Generally performed on NX-size core.

Revised 9/2012


Slide 123 of 125

ROCK MASS RATING (RMR)• RMR based on five parameters:

– Uniaxial strength (qu)– Rock Quality Designation (RQD)– Spacing of Discontinuities– Condition of the Discontinuities– Groundwater Conditions

• RMR = R1+R2+R3+R4+R5

• Adjustment for Joint Orientation relative to construction


Revised 9/2012


Slide 124 of 125

02468

10121416

0 50 100 150 200 250 300

Unconfined Compressive Strength, qu (MPa)

RM

R R

atin

g R

1

0

5

10

15

20

25

0 10 20 30 40 50 60 70 80 90 100Rock Quality Designation, RQD

RM

R R

atin

g R

2

0

5

10

15

20

25

0.01 0.1 1 10Joint Spacing (meters)

RM

R R

atin

g R

3

0

5

10

15

20

25

30

35

0 1 2 3 4 5 6Joint Separation or Gouge Thickness (mm)

RM

R R

atin

g R

4 Slightly Rough Weathered

Slickensided Surface or Gouge-Filled

Soft Gouge-Filled

Rough/Unweathered

ROCK MASS RATING (RMR)Geomechanics Systems (CSIR) [after Bieniawski, 1984, 1989]


Revised 9/2012


Slide 125 of 125

0

2

4

6

8

10

12

14

16

0 0.1 0.2 0.3 0.4 0.5 0.6Joint Water Pressure Ratio, u/1

RM

R R

atin

g R

5

u = joint water pressure1 = major principal stress

Al ter nate 2 Def i ni t

f or P ar ameter R5

0

2

4

6

8

10

12

14

16

1 10 100 1000

Inflow per 10-m Tunnel Length (Liters/min)

RM

R R

atin

g R

5

Al t er nat e 1 Def i ni t i

f or P arameter R5

Dry

Damp

Wet

Dripping

Flowing

ROCK MASS RATING (RMR) also CSIR System 5

Geomechanics System - (Bieniawski, 1984, 1989) RMR = Ri Geomechanics Classification for Rock Masses i = 1 CLASS DESCRIPTION RANGE of RMR

I Very Good Rock 81 to 100 NOTE: Rock Mass Rating is obtained by summing the five index II Good Rock 61 to 80 parameters to obtain an overal rating RMR. Adjustments for dip III Fair Rock 41 to 60 and orientation of discontinuities being favorable or unfavorableIV Poor Rock 21 to 40 for specific cases of tunnels, slopes, & foundations can also beV Very Poor Rock 0 to 20 considered.

ROCK MASS RATING (RMR)Geomechanics Systems (CSIR) [after Bieniawski, 1984, 1989]


14.528 drilled deep foundations soil...

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