253. As per ISI (18:1498-1970) the classification and identification of soils for general engineering purpose are: 1. Coarse grained soils contain total material by weight larger than 75 microns IS sieve size. 2. Fine grained soils contain total material by weight smaller than 75 micron IS sieve size 3. Highly organic soils contain large percentages fibrous organic matter. Of these statements:
A. 1 alone is correct
B. 2 alone is correct
C. 2 and 3 are correct
D. l2 and 3 are correct.
254. Consider the following statements regarding the factors affecting permeability of soils1. Permeability varies approximately as the square of the grain size 2. Permeability is directly proportional to the unit coefficient of water and its viscosity 3. Permeability is greatly influenced in fine grained soils 4. Permeability is reduced in the presence of organic matter Of these statements:
A. 1, 2 and 3 are correct
B. 2, 3 and 4 are correct
C. 1, 3 and 4 are correct
D. 1, 2, 3 and 4 are correct
255. Consider the following statements regarding the seepage in soils 1. The pressure of the pore water at the water table is atmospheric of 2. Water table is also called phreatic surface 3. Artesian conditions exist if an inclined soil layer of low permeability is confined locally by an overlying layer of high permeability 4. The attraction of the particles by pore water above the water table is called soil suction Of these statements:
A. 1, 2 and 3 are correct
B. 2, 3 and 4 are correct
C. 1, 2 and 4 are correct
D. 1, 3 and 4 are correct.
256. Consider the following statements regarding the permeability of soils 1. The coefficient of permeability is the ratio of discharge velocity and hydraulic gradient 2. The presence of a small percentage of fines in a coarsegrained soil raises the permeability 3. The coefficient of permeability of a soil is a function of its void ratio 4. In stratified soil permeability in the direction of stratification is less than that in perpendicular direction.Of these statements:
A. 1, 2 and 3 are correct
B. 2, 3 and 4 are correct
C. 1, 3 and 4 are correct
D. 3 and 4 are correct.
257. Consider the following statements regarding the coefficient of permeability of soil.1. For coarse-grained soils, the constant head permeability test is performed 2. For fine grained soils, the falling head permeability test is performed 3. For homogenous coarse-grained soil strata, well pumping test is suitably employed. Of thes e statements:
A. 1 alone is correct
B. 1, 2 and 3 are correct
C. 2 and 3 are correct
D. 3 alone is correct.
258. Consider the following statements regarding the flow nets in seepage flow in soils 1. Every intersection of a flow line and an equipotential is made at right angles 2. 2. Difference in flows (Ay) between any two adjacent flow lines is the same3. Difference in potentials (A )) between two adjacent4. The flow lines and equipotentials form curvilinear equipotentials. rohmbuses. Of these statements:
A. 1 and 2 are correct
B. 2 and 3 are correct
C. 1, 2 and 3 are correct
D. 3 and 4 are correct
259. Consider the following statements regarding anisotropic soils 1. The coefficient of permeabily has maximum value in the direction of stratification 2. The coefficient of permeability has minimum value in the direction normal to the direction of stratification 3. The coefficient of permeability has same value in both the directions. Of these statements:
A. 1 alone is correct
B. 1 and 2 are correct
C. 2 and 3 are correct
D. 1, 2 and 3 are correct
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