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Lectures, exercise and some answer for practicing. Mr SEANG POV is one of best professor in soil mechanic in cambodia

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  • Advance Soil mechanics Present by Mr. Sieng PEOU

    Master science of geotechnical engineering

  • Soils particle size

    19.5mm>d>4.76mm.

    Gravel

    4.76mm>d>0.075mm

    Sand

    Coarse grained soils

    0.075mm>d>0.002mm

    Silt

    d

  • Sieve analysis method

    For coarse grained soils

  • Retained cumulative

    %R= %100

    .

    ..

    weighttotal

    cumulativeretainedweight

    Passing cumulative

    %P = 100-%R

  • Logarithm scale

    Logd

    0.001 0.01 0.1 1 10 100

    a

    If 0.001

  • Hydrometer analysis

    For fine grained soils

  • Hydrometer analysis

    %100*%SW

    RRaP +=

    TLKD =

    P%-passing cumulative

    a- soil factor

    R-hydrometer reading

    R-corrected factor

    Ws-weight of dry soil

    D-soil diameter

    K-hydrometer factor

    L-depth of hydrometer in

    Solution

    time in minute

  • Soil particle size curve Uniformity coefficient UC=D60/D10

    d10 d60

  • Weight and volume relation ship

    V

    Va

    Vw

    Vs

    W

    Wa=0

    Ww

    Ws

  • W=Ws+Ww

    V=Va+Vw+Vs

    Vv =Va+Vw

    V= Vv+Vs

  • Soils sampling Disturbed sample for determine properties

    physics of soils Undisturbed sample for determine

    properties mechanics of soils, we call undisturbed when AR(%)

  • Soils unit weight Natural water content:

    Bulk unit weight:=

    Dry unit weight: d=

    Unit weight of particle solid: s=

    ws

    e

    eSGVW

    +

    +=

    1

    s

    s

    VW

    1001

    +

    =

    VW s

    %100=s

    w

    WW

  • Another parameter Void ratio:

    Degree of saturation:

    Saturated unit weight:

    Effective unit weight:

    d

    ds

    s

    v

    VV

    e

    ==

    w

    s

    v

    w

    eVVS

    == %100

    Ws

    sate

    eG

    +

    +=

    1

    ws

    wsate

    G

    +

    ==

    11

    '

  • Another parameters Specific gravity:

    Relative density:

    Saturated water content:

    ws

    ss V

    WG

    =

    %100minmax

    max

    =

    ee

    eeDR

    %10011

    = w

    sdsat

  • Typical values of unit weight of soils

    Soil type sat(KN/M3) d(KN/M3)

    Gravel 20 to 22 15 to 17

    Sand 18 to 20 13 to 16

    Silt 18 to 20 14 to 18

    Clay 16 to 22 14 to 21

  • Description based on Relative density

    DR(%) Description 0 to 15 Very loose 15 to 35 Loose

    35 to 65 Medium dense 65 to 85 Dense

    85 to 100 Very dense

  • Soil consistence

    ShrinkagelimitWs

    PlasticlimitWp

    LiquidlimitWL

    Atterberglimit

  • State of cohesion soils Plastic index IP=WL-WP

    Liquidity index IL=

    P

    P

    I

  • State of cohesion soils

    If 0

  • CH

    MH CL

    ML

    CL-ML

  • Soil classification USCS:Unified soil classification system

    (ASTM Test Designation D-2487) ASTM: American Society for Testing and Materials Proposed by Casagrande in 1942,this system was revised in 1952 by U.S Bureau of Reclamation.

  • Coarse grained soils

    %R(4.76mm)>0.5%R(0.075mm)Gravel

    %R(4.76mm)50%Coarse grained soils

  • Gravel

    UC4Well graded Gravel

    GW

    Clean Gravel%P(0.075mm)

  • Gravel

    Located CL or CHPoorly gradedclayey Gravel

    GC-GP

    Located ML or MHPoorly graded silty Gravel

    GM-GP

    Located CL-MLPoorly graded clayey

    silty GravelGC-GM-GP

    UC4On plastic Chart Casagrande

    Mixed Gravel5%

  • Gravel

    Located CL or CHclayey Gravel

    GC

    Located ML or MH silty Gravel

    GM

    Located CL-ML clayey silty Gravel

    GC-GM

    Mixed Gravel%P(0.075mm)>12%

  • Sand

    UC6Well graded Sand

    SW

    Clean Sand%P(0.075mm)

  • Sand

    Located CL or CHPoorly gradedclayey Sand

    SC-SP

    Located ML or MHPoorly graded

    silty SandSM-SP

    Located CL-MLPoorly graded clayey

    silty SandSC-SM-SP

    UC6On plastic Chart Casagrande

    Mixed Sand5%

  • Sand

    Located CL or CHclayey Sand

    SC

    Located ML or MH silty Sand

    SM

    Located CL-ML clayey silty Sand

    SC-SM

    Mixed Sand%P(0.075mm)>12%

  • Fine grained soils

    CL CH

    For Clay

    ML MH

    For Silt

    CL-ML

    For Silty clay

    %R(0.075mm)

  • Lean Clay(CL)

    %S>%GLean ClayWith sand

    %S

  • Fat Clay(CH)

    %S>%GFat Clay

    With sand

    %S

  • Silt (ML)

    %S>%GSilt

    With sand

    %S

  • Elastic Silt (MH)

    %S>%GElastic SiltWith sand

    %S

  • Silty clay (CL-ML)

    %S>%GSilty clay

    With sand

    %S

  • Soil classification AASHTO:Association American for

    State Highway and Transportation official, was developed 1929 and proposed by the committee on Materials for sub grades and Granularity Type Boards of the Highway Research Road in 1945(ASTM Test designation D-3282;AASHTO method M145)

  • Granular Materials %P(0.075mm)
  • Silty - clay material %P(0.075mm)>35% Group classification A-4 A-5

    A-6

    A-7 A-7-5 A-7-6

    %P(2mm) %P(0.425mm) %P(0.075mm) >35% >35% >35%

    >35%

    WL 40 40 IP 10 Usual type of materials

    Silty soils Clayey soils

    General subgrade rating

    Fair to poor

    For A-7-5: IPWL-30

  • Group index GI

    GI=(%P(0.075)-35)[0.2+0.005(WL-40)]+0.01(%P(0.075)-15)(IP-10)

  • Soil compaction Standard Proctor test

    Modified Proctor test

  • Specification for standard Proctor test(based on ASTM test designation 698-91)

    Item Method A Method B Method C Diameter of mold 101.6mm 101.6mm 152.4mm

    Volume of mold 943.3cm3 943.3cm3 2124cm3 Weight of hammer 24.4 N 24.4 N 24.4 N Height of hammer drop 304.8mm 304.8mm 304.8mm Number of hammer blows per layer

    25 25 56

    Number of layer of compaction

    3 3 3

    Energy of compaction 591.3KNm/m3 591.3KNm/m3 591.3KNm/m3 Soil to be used %R(4.75)20% %R(9.5)20% %R(19)

  • Specification for modified Proctor test(based on ASTM test designation 1557-91)

    Item Method A Method B Method C Diameter of mold 101.6mm 101.6mm 152.4mm

    Volume of mold 943.3cm3 943.3cm3 2124cm3 Weight of hammer 44.5 N 44.5 N 44.5 N Height of hammer drop 457.2mm 457.2mm 457.2mm Number of hammer blows per layer

    25 25 56

    Number of layer of compaction

    5 5 5

    Energy of compaction 2696KNm/m3 2696KNm/m3 2696KNm/m3 Soil to be used %R(4.75)20% %R(9.5)20% %R(19)

  • Compaction equipment

  • Compaction curve MOISTURE DENSITY RELATIONSHIP CURVE

    1.900

    2.000

    2.100

    2.200

    0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00

    Moisture content %

    D

    r

    y

    D

    e

    n

    s

    i

    t

    y

    g

    /

    m

    3

    Wopt

    dmax

  • California Bearing Ratio(CBR) For study the strength of soils after

    compacting in optimum state. 1-Recompaction the soil in optimum

    state 2-Determine CBR in dry condition 3-Saturated the soil under water 4 days 4-Determine CBR in soaked condition CBR=

    %100..standard

    ..

    loadunit

    loadunitTest

  • BEARING RATIO TEST (CBR)

    Project: Pochentong Airport Job No.Location of Project: Pochentong Airport Boring No 2 Sample No.2Description of Soil: Tested by: Mr. Men Tharith Date of Testing. 16/05/2002

    CBR Test Load Data (soaked)Mold

    Surrcharge Piston load Load.

    Penetration. dial reading kgf/cm2

    mm ( unit )0.000 0 01.00 0.045 2.30772.00 0.075 3.84623.00 0.11 5.6414.00 0.145 7.43595.00 0.175 8.97446.00 0.21 10.7697.00 0.25 12.8218.00 0.28 14.3599.00 0.31 15.89710.00 0.34 17.436

    CBR(2.54)= 7.1429

    Acceppted CBR= 7.14

    Final water Top 7.9conten, w% Midle 7.8

    (soaked) Bottom 7.99sample Averagee 7.8967

    Wet unit wt. = 2.2952 g/cm3 Dry unit wt. = 2.13444 g/cm3

    Wet unit wt.(soaked) = 2.303 g/cm3

    Curve CBR Test

    0

    2

    4

    6

    8

    10

    12

    14

    16

    18

    20

    0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0

    Renetration (mm)

    L

    o

    a

    d

    (

    k

    g

    f

    /

    c

    m

    2

    )

    P2.54

  • Penetration(mm) Standard unit load(Mpa)

    2.5 6.9

    5 10.3

    7.5 13

    10 16

    12.7 18

  • CBR equipment

  • CBR equipment

  • CBR special for field control Compaction the soils in optimum state

    with different energy 1-Compaction 10 blows per layer and

    saturated the soil under water during 4 days

    2-Compaction 25 blows per layer and saturated the soil under water during 4 days

    3-Compaction 55 blows per layer and saturated the soil under water during 4 days

    4-Determine CBR in soaked condition for

  • CBR chart

  • CBR General rating

    Uses Classification system

    USCS AASHTO

    0-3 Very poor

    Subgrade

    OH,CH,MH,OL

    A5,A6,A7

    3-7 Poor to fair

    Subgrade

    OH,CH,MH,OL

    A4,A5,A6,A7

    7-20 Fair Subbase OL,CL,ML,SC,SM,SP

    A2,A4,A6,A7

    20-50 Good Base subbase

    GM,GC,SW, SM,SP,GP

    A1b,A2-5, A3,A2-6

    >50 Excellent