#### Residual soil are formed by

a. Glaciers– glaciers are large masses of ice formed by the compaction of Snow. As the glacier grow and move, they carry with them soils varying in size from fine grained to huge boulders. Soils get mixed with the ice and are transported far away from their original position. Ex. – Drift soil b. Wind– Soils deposited by wind are know as aeolian deposit, loess and sand dunes. c. Water – 1. Alluvial soil – transported by water are settled on river bed. 2. Lacustrine Soils – These are deposited by still water agents such as lakes. 3. Marine Soils – Deposited by salty water or ocean water. d. Gravity - Deposited in the lower part of the mountains, ex. Colluvial Soils/Talus

#### Water content of soil can

The water content is defined as the ratio of the weight of water to the weight of solids. W (in%) = Ww/Ws × 100

#### Which of the following types of soil is transported by gravitational force

a. Loess and aeolian soil – formed by Wind b. Talus/ Colluvial Soil – Gravitational force c. Drift – Glaciers d. Dune sand – Formed by wind

#### A fully saturated soil said to be

#### Valid range for S, the degree of saturation of soil in percentage is

The degree of saturation is ratio of the volume of water to the volume of voids. S = Vw/Vv S = Vw/(Vw+Va) For dry soil, S=0 For Fully saturated soil, S=1

#### The submerged density of soil in terms of unit weight of water Yw, Specific gravity G and void ratio e is the given by the expression

1. Bulk/Wet/Moist/Total unit weight = (G+eS) Yw/(1+e) 2. Saturated unit weight, Ysat. = (G+e) Yw/(1+e) 3. Dry unit weight, Yd = GYw/(1+e) 4. Submerged unit weight, Ysub. = (G-1) Yw/(1+e)

#### A soil has a bulk density of 22KN/m³ and water content 10%. The dry density of soil is

Bulk density = Dry density × (1 + Water content) Yb = Yd (1+W) 22 = Yd (1+0.10) Yd = 20 KN/m³

#### If the voids of a soil mass are full of air only, the soil as termed as

#### Valid range for n, the percentage air voids, is

Percentage air voids:- It is the ratio of the volume of air to the total volume. n = Va/V × 100 - Va always less than total volume (V) - For fully saturated soil, Va=0

#### Select the correct statement

Ysat. > Yb > Yd > Ysub.

#### Void ratio of a soil mass can

Void ratio(e) is defined as the ratio of volume of voids(Vv) to the volume of solids(Vs). e = Vv/Vs *Vv can be greater than, less than or equal to Vs

#### If the Volume of voids is equal to the volume of solids in a soil mass, then the values of porosity and void ratio respectively are

Volume of voids (Vv) = Volume of solids (Vs) 1. Porosity, n = Vv/V n = Vv/(Vv+Vs) n = Vv/2Vv n = 0.5 2. Void Ratio, e = Vv/Vs e = Vv/Vs e = 1

#### When the degree of saturation is zero, the soil mass under consideration represents

#### Select the correct range of density index

Density Index or Relative density or Degree of density Id = (emax. – e) /(emax.-emin.) If natural soil in loose condition, e = emax. and Id = 0 If natural soil in dense condition, e = emin. and Id = 1

#### If the degree of saturation of a partially saturated soil is 60%, then air content of soil is

Degree of saturation (S) = Vw/Vv. Air content (ac) = Va/Vv. Degree of saturation + air content = 100 % . S + ac = 1 60 + ac = 1 ac = 40%

#### If the water content of a fully saturated soil mass is 100%, then the voids ratio of the sample is

Fully saturated soil, S = 100% or 1 Water content, W = 100% or 1 We know that, eS = GW e . 1 = G . 1 e = G

#### The ratio of volume of voids to the total volume of soil mass is called

a. Air content – The ratio of volume of air to the volume of the voids. b.Porosity – The ratio of volume of the voids to the total volume of soil mass. c. Percentage air voids – The ratio of volume of air to the total volume of soil mass. d. Voids ratio – The ratio of volume of voids to the volume of solids.

#### Relative density of a compacted dense sand is approximately equal to

Relative density for compacted dense sand is approximately is 0.85 to 1.0. Practically 100% compaction is not possible.

#### If the sand in-situ is in it’s densest state, then the relative density of sand is

Relative density of densest sand is 1

#### Which of the following methods is most accurate for the determination of the water content of soil

a. Oven drying – Standard and accurate lab method. b. Sand bath method – Same as Oven drying except drying in sand bath. c. Calcium carbide method – Rapid method. d. Pycnometer metod – Only for coarse grain soil (If G is known).

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