Soil Mechanics And Foundation MCQ Questions & Answers | Civil Engineering

Option A: "The greater the viscosity, the greater is permeability."
This statement is incorrect because viscosity refers to the resistance of a fluid to flow, not to the soil's ability to transmit water. Permeability is determined by factors such as pore size and connectivity within the soil, rather than by the viscosity of the fluid.

Option B: "The greater the unit weight, the greater is permeability."
This statement is incorrect because, as discussed earlier, higher unit weight (density) usually results in smaller pore spaces within the soil, leading to decreased permeability, not increased permeability.

Option C: The greater the unit weight, the smaller is permeability.
Permeability refers to the ability of a soil to transmit water or other fluids through it.
Unit weight (also known as density) affects permeability. The greater the unit weight of soil, the smaller is its permeability.
This is because denser soil has smaller pore spaces between particles, which restricts the movement of water or fluids through the soil mass.

Option D: "Unit weight does not affect permeability."
This statement is incorrect. As explained previously, unit weight (density) does affect permeability. Higher unit weight typically results in smaller pore spaces and decreased permeability.

Therefore, the correct statement is Option C: "The greater the unit weight, the smaller is permeability."

The correct answer is C: ML.
Let's break down why:
Soil Classification: In soil mechanics, we use a system to classify different types of soil. This helps us predict how the soil will behave.
Inorganic vs. Organic Soils: Inorganic soils are made of minerals, like sand, silt, and clay. Organic soils contain a lot of decomposed plant and animal matter.
Compressibility: Compressibility refers to how much a soil's volume decreases under pressure. Low compressibility means the soil doesn't shrink much when you put weight on it.
The Options Explained:
MH: This represents inorganic silts with high compressibility.
SL: This is not a standard soil classification symbol.
ML: This represents inorganic silts with low compressibility. This is exactly what the question is asking for!
CH: This represents inorganic clays with high compressibility.
Therefore, ML (inorganic silts with low compressibility) is the right answer.