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INDEX

Specific Gravity of Common Minerals

Void ratio, Moisture Content, and Dry Unit Weight for Some Typical Soils in a Natural State

Qualitative Description of Granular Soil Deposits

Typical Values of Liquid Limit, Plastic Limit, and Activity of Some Clay Minerals

Typical Values of Hydraulic Conductivity of Saturated Soils

Empirical Relationships for Estimating Hydraulic Conductivity

Approximate Range of Capillary Rise in Soils

Representative Values of the Modulus of Elasticity of Soil

Representative Values of Poissons Ratio

Correlations for Compression Index Cc

Variation of sin with plasticity index for a number of soils

General Relationship of Consistency and Unconfined Compression Strength of Clays

Spacing of borings

Approximate Correlations of Standard Penetration Number and Consistency of Clay

Approximate Relationship Between Corrected Standard Penetration Number and Relative Density of

Sand

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Specific Gravity of Common Minerals

Mineral Specific Gravity, Gs

Quartz 2.65

Kaolinite 2.6

Illite 2.8

Montmorillonite 2.652.80

Halloysite 2.02.55

Potassium feldspar 2.57

Sodium and calcium feldspar 2.622.76

Chlorite 2.62.9

Biotite 2.83.2

Muscovite 2.763.1

Hornblende 3.03.47

Limonite 3.64.0

Olivine 3.273.7

Void ratio, Moisture Content, and Dry Unit Weight for Some Typical Soils in a Natural State

Type of soil Void ratio, eNatural moisture content

in a saturated state (%)

Dry unit

weight, d

kN/m3

Loose uniform sand 0.8 30 14.5

Dense uniform sand 0.45 16 18

Loose angular-grained silty sand 0.65 25 16

Dense angular-grained silty sand 0.4 15 19Stiff clay 0.6 21 17

Soft clay 0.91.4 3050 11.514.5

Loess 0.9 25 13.5

Soft organic clay 2.53.2 90120 68

Glacial till 0.3 10 21

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Qualitative Description of Granular Soil Deposits

Relative Density (%) Description of soil deposit

015 Very loose

1550 Loose

5070 Medium

7085 Dense

85100 Very dense

Typical Values of Liquid Limit, Plastic Limit, and Activity of Some Clay Minerals

Mineral Liquid limit, LL Plastic limit, PL Activity, A

Kaolinite 35100 2040 0.30.5

Illite 60120 3560 0.51.2

Montmorillonite 100900 50100 1.57.0

Halloysite (hydrated) 5070 4060 0.10.2

Halloysite (dehydrated) 4055 3045 0.40.6

Attapulgite 150250 100125 0.41.3

Allophane 200250 120150 0.41.3

Sridharan et al. (1999) showed that the plasticity index can be correlated to the flow index as obtained

from the liquid limit tests. According to their study,

%= 4.12% %= 0.741%

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Typical Values of Hydraulic Conductivity of Saturated Soils

Soil typek

cm/sec

Clean gravel 1001.0

Coarse sand 1.00.01

Fine sand 0.010.001

Silty clay 0.0010.00001

Clay

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Approximate Range of Capillary Rise in Soils

Soil type

Range of capillary

rise

m

Coarse sand 0.11.2Fine sand 0.31.2

Silt 0.757.5

Clay 7.523

Representative Values of the Modulus of Elasticity of Soil

Soil typeEs

kN/m2

Soft clay 18003500

Hard clay 600014000

Loose sand 1000028000

Dense sand 3500070000

Representative Values of Poissons Ratio

Type of soil Poissons ratio, s

Loose sand 0.20.4

Medium sand 0.250.4

Dense sand 0.30.45

Silty sand 0.20.4

Soft clay 0.150.25

Medium clay 0.20.5

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Correlations for Compression Index Cc*

Equation Reference Region of applicability

Cc = 0.007(LL-7) Skempton (1944) Remolded clays

Cc = 0.01wN Chicago clays

Cc = 1.15(e0-0.27) Nishida (1956) All clays

Cc = 0.30(e0-0.27) Hough (1957) Inorganic cohesive soil: silt, silty clay, clay

Cc = 0.115wN Organic soils, peats, organic silt, and clay

Cc = 0.0046(LL-9) Brazilian clays

Cc = 0.75(e0-0.5) Soils with low plasticity

Cc = 0.208e0+0.0083 Chicago clays

Cc = 0.1556e0+0.0107 All clays

*After Rendon-Herrero (1980)

e0= in situ void ratio; wN= in situ water content

On the basis of observations on several natural clays, Rendon-Herrero (1983) gave the relationship for

the compression index in the form

= 0.141. (1 + ).8

Nagaraj and Murty (1985) expressed the compression index as

= 0.2343 [%100 ]

The swell index is appreciably smaller in magnitude than the compression index and can generally be

determined from laboratory tests. In most cases,

15 1

10

The swell index was expressed by Nagaraj and Murty (1985) as

= 0.0463 [%100 ]

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Variation of sinwith plasticity index for a number of soils (after Kenney, 1959)

General Relationship of Consistency and Unconfined Compression Strength of Clays

Consistency qu( kN/m2)

Very soft 025

Soft 2550

Medium 50100

Stiff 100200

Very stiff 200400

Hard >400

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Spacing of borings

Project Boring spacings (m)

One-story buildings 2530

Multistory buildings 1525

Highways 250300

Earth dams 2550

Residential subdivision planning 60100

Approximate Correlations of Standard Penetration Number and Consistency of Clay

Standard

Penetration

number,N

Consistency Unconfined

compression

strength

(kN/m2)0 0

2

Very soft

25

4

Soft

50

8

Medium stiff

100

16

Stiff

200

32

Very stiff

400

>32

Hard

>400

Approximate Relationship Between Corrected Standard Penetration Number and Relative Density of

Sand

Corrected standard penetration

number, Ncor

Relative

density, Dr

05 05

510 530

1030 3060

3050 6095