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Soil Mechanics - Compressibility of Soil, Consolidation & Compaction

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1. Time factor    for (a) U > 50% (b) U ≤ 60% (c) U > 60% (d) U ≤ 50% 2. The time required for a soil to reach a given degree of consolidation is directly proportional to (a) cube of drainage path (b) drainage path (c) square of drainage path (d) coefficient of consolidation 3. The time required for a soil to reach a given degree of consolidation is inversely proportional to (a) time factor (b) coefficient of consolidation (c) drainage path (d) square of drainage path 4. Oedometer is used for (a) permeability test (b) shear strength test (c) seepage test (d) consolidation test 5. In a soil sample of a consolidometer test, pore water pressure is (a) minimum at the centre (b) maximum at the top (c) maximum at the bottom (d) maximum at the centre (IES 1993) 6. Coefficient of consolidation is determined by (a) Casagrande’s Logarithm of time fitting method (b) Taylor’s square root of time fitting method (c) both (a) and (b) (d) neither (a) nor (b) 7. When the effective stress is plott

Soil Mechanics - Compressibility of Soil, Consolidation & Compaction

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1. In case of single drainage, the maximum distance that water has to travel to reach a drainage face(length of longest drainage path) is equal to (a) thickness of clay layer (b) double the thickness of clay layer (c) half the thickness of clay layer (d) none of these 2. The identical clay samples of the same size, designed as “A” and “B” are subjected to consolidation tests under identical loading conditions. Drainage takes place through one face in sample “A” and through both faces in sample “B”. 50% consolidation of sample “A” occurs in 10 minutes. The time required for 50% consolidation to occur in sample “B” will be (a) 40 minutes (b) 10 minutes (c) 5 minutes (d) 2.5 minutes (IES 1995) 3. A clay layer 5 m thick in field takes  300 days to attain 50% consolidation with condition of double drainage. If the same clay layer is underlain by hard  rock then the time taken to attain 50% consolidation will be (a) 300 days (b) 600 days (c) 900 days (d) 1200 days (IES 1996) Hint:  4. A satu

Soil Mechanics - Compressibility of Soil, Consolidation & Compaction

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1. According to Terzaghi’s theory (a)   (b)   (c)   (d) none of these Where   is coefficient of consolidation. 2. Terzaghi’s one-dimensional consolidation theory assumes that (a) e versus p relationship is linear (b) e versus log₁₀ p relationship is linear (c) p versus log₁₀ e relationship is linear (d) e versus log₁₀ (p/p₀) is linear (GATE 1991) 3. Terzaghi’s consolidation theory is applicable to one-dimensional consolidation test (a) for small load increment ratios (b) for large load increment ratios (c) for a load increment ratio of nearly one (d) in situations where there is no excess pore pressure (IES 1998) 4. Unit of the coefficient of consolidation is (a) m³/year (b) m⁴/year (c) m/year (d) m²/year 5. The relationship between coefficient of compressibility( ) and coefficient of consolidation( ) is (a)  (b)   (c)   (d)   6. Which one of the following statements regarding the coefficient of consolidation   is correct? (a)  (b)  (c)  (d)  (IES 2002) 7. The coefficient of consol

Soil Mechanics - Compressibility of Soil, Consolidation & Compaction

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1. The virgin compression curve for a particular soil is shown in the given figure. The compression index of the soil is (a) 0.35 (b) 0.50 (c) 1.0 (d) 1.5 (IES 1994) Hint:  2. When a stress is applied to a saturated soil, its volume reduces and effective stress (a) decreases (b) increases (c) remains unaltered (d) first decreases then increases 3. Compressibility of a soil sample decreases as the effective stress (a) increases (b) decreases (c) first decreases then increases (d) none of these 4. The slope of void ratio(e) versus effective stress plot is called (a) compression index (b) coefficient of compressibility (c) coeff. of permeability (d) coeff. of compressibility 5. In a soil sample if void ratio decreases with increases with stress, coefficient of compressibility will be (a) positive (b) negative (c) any sign (d) none of these 6. In a soil sample, with increase in effective stress, coefficient of compressibility (a) decreases (b) increases (c) remains unchanged (d) any of the

Soil Mechanics - Compressibility of Soil, Consolidation & Compaction

1. Escape of pore water from a soil is very quick. The soil would be (a) clay (b) peat (c) silt (d) sand 2. Escape of pore water from a soil is very slow. The soil would be (a) clay (b) peat (c) silt (d) sand 3. When a soil is stressed to a level greater than the maximum stress to which it was ever subjected in the past then (a) no further compressibility occurs (b) much higher compressibility occurs (c) much lower compressibility occurs (d) piping occurs 4. Between recompression curve and a virgin compression curve for a soil sample, there is a point corresponding to the maximum value of stress the soil has ever experienced. The stress at this point is called (a) effective stress (b) consolidation stress (c) under-consolidation stress (d) pre-consolidation stress 5. In a soil if the existing effective stress is the maximum that it has ever experienced in its history, then the soil will be called (a) normally consolidated (b) pre-consolidated (c) under-consolidated (d) none of these 6.

Soil Mechanics - Compressibility of Soil, Consolidation & Compaction

1. The total settlement of soil comprises of (a) immediate settlement (b) settlement due to primary consolidation (c) settlement due to secondary consolidation (d) all these 2. Settlement due to secondary consolidation is also called (a) creep settlement (b) effective settlement (c) distortion settlement (d) none of these 3. Immediate settlement is also called (a) creep settlement (b) effective settlement (c) distortion settlement (d) none of these 4. The squeezing out of pore water from a loaded saturated soil causing a decrease in volume is known as (a) immediate settlement (b) creep settlement (c) primary consolidation (d) none of these (IES 2000) 5. At the end of primary consolidation (a) pore pressure dissipate (b) rate of flow will decrease (c) flow ceases altogether eventually (d) all of the above 6. At the end of primary consolidation (a) constant effective stress prevails (b) some soils exhibit a further time dependent settlement (c) both (a) and (b) (d) neither (a) nor (b) 7.

Soil Mechanics - Seepage of Soils

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1. A flow net is drawn to obtain (a) seepage, coefficient of permeability and uplift pressure (b) coefficient of permeability, uplift pressure and exit gradient (c) exit gradient, uplift pressure and seepage quantity (d) exit gradient, seepage and coefficient of permeability (IES 1995) 2. The possibility of quick sand condition will be there when flow of water to soil is (a) horizontal (b) upwards (c) downwards (d) radial 3. Piping can occur in a soil mass when (a) upward acting seepage pressure ≥ downward acting submerged weight of the soil above it (b) upward acting seepage pressure < downward acting submerged weight of the soil above it (c) upward hydraulic gradient approaches unity (d) (a) and (c) 4. Piping in soil occurs when (a) the soil is highly porous (b) sudden change in permeability occurs (c) effective pressure becomes zero (d) the soil is highly stratified (GATE 1996) 5. Hydraulic gradient at exit is called (a) critical exit gradient (b) exit gradient (c) piping (d) n