1. Soil Classification

7/29/2019 1. Soil Classification

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Highway Engineering


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GEOMETRIC DESIGN

STRUCTURE DESIGN

:-

(No of lanes)

(Horizontal Curves)

(Intersections)

:-

(Soil Classification)

(Pavement Stresses)

(Pavement Design)


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Soil States

The stress strain response of a soil is highly affected by its

natural moisture content, its location with respect to the valueof Atterberg limits as shown in figure. The figure shows that

soil cannot support any stress if its natural moisture content is

more than the liquid limit (the soil is in liquid state). On the

other hand the soil can support more loads when the moisturecontent is less than its plastic limit(the soil is in the solid state).

0 SL PL LL

Solid Semi-Solid

Plastic Liquid


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Relationship

W LL

0 S

L

P

L

L

L

Solid Semi-

Solid

Plastic Liquid


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Classification


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SoilTests

Sieve Analysis Atterberge Limits


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0.0

6.5133.9237.3310.1374.3434.3517.3539.7

0.0

1.224.844.057.569.480.595.8

100.0

100.0

98.975.256.042.630.619.5

4.20.0

Sieve Analysis

9.54.752.361.180.600.30

0.150.075

Pan

0.0

6.5127.4103.4

72.864.260.083.022.4

Passing % Retain. % Retain. Retain Sieve

Cumulative.


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LIQUID LIMIT FLOW LINE

19

20

21

22

23

13 15 17 19 21 23 25 27 29 31 33 35 37 39 41

NUMBER O F BLOWS

MOISTURECONTENT

Liquid Limits

LIQUID LIMIT UNITTRIAL NO.

1 2 3

TARE NO. 104 B 103

GROSS WET MASS g 58.240 49.460 51.270

GROSS DRY MASS g 54.070 46.130 48.770

MOISTURE MASS g 4.170 3.330 2.500

TARE MASS g 35.380 30.170 36.240

DRY SOIL MASS g 18.690 15.960 12.530

MOISTURE CONTENT % 22.31 20.86 19.95

NO. OF BLOWS 18 25 31


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PLASTIC LIMIT UNITSTRIAL NO.

1 2 3TARE NO. 3 P 7

GROSS WET MASS g 13.85 15.84 16.71

GROSS DRY MASS g 13.560 15.620 16.380

MOISTURE MASS g 0.290 0.220 0.330

TARE MASS g 11.77 14.23 14.29

DRY SOIL MASS g 1.790 1.390 2.090

MOISTURE CONTENT % 16.20 15.83 15.79

TEST SUMMARY

L.L P.L P.I

21.0 16.0 4.9

Plastic Limits


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Group Index (GI)

GI = 0.2a + 0.005ac + 0.01bdwhere:

a = F 35 (0 40)

b = F 15 (0 40)

c = LL 40 (0 20)

d = PI 10 (0 20)

Fis passing 200

PI = LL - PL

RatingGI

Excellen

t

0

Good1

Fair2-4

Poor5 -9

Very

Poor

10 - 20


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Classification


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PLLLNo. 200No. 40No. 10Sieve

33423055-(Soil A), %

15358596100(Soil B), %

Example

Soil A

%age passing No. 200 is 30% (< 35%)Soil is Course, It may be

A-1, A-2, A-3%age passing No. 40 is 55% Soil could be A-2, or A-3

%age passing No. 200 is 30% (>10%)Soil is A-2 Using Chart to

deter. Type

Soil is (A

2- 5)GI = 0.2a + 0.005 ac + 0.01 bd

a = 30 35 = 0

b = 30 15 = 15

c = 42 40 = 2

d = 9

10 = 0


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LL

PI

A -6A 2-6

A-4A 2-4

A - 7 - 6

A - 7 5A 2 -7

A-5A -2-5

10

40


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Example

%age passing No. 200 is 86% (>35%) Soil is Fine, It may be A-

4, A-5, A-6, A-7

Diagonal line is (LL 30 = 70 30 = 40) PI = 32 < 40, and

Using the figure soil is (A 7- 5)

GI = 0.2a + 0.005 ac + 0.01 bda = 86 35 = 51 (40)

b = 86 15 = 71 (40)

c = 70 40 = 30 (20)

d = 32

10 = 22 (20)GI = 0.2*51+ 0.005*51*30+0.01*71*22= 33.47(very poor)

GI = 0.2*40 + 0.005*40*20 + 0.01*40*20=20 (very poor)

Soil is (A 7- 5) (33.47)


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Documents

1. Soil Classification