Permeability MCQ with answer and solution

Concept

Permeability test method for coarse-grained soils

Formula

NONE

Step-by-step solution

1. Permeability tests are selected based on the grain size and expected discharge of the soil sample. 2. Coarse-grained soils like gravels and sands have high permeability, allowing a continuous discharge under constant head. 3. The constant head permeability method is best suited for coarse-grained soils, while the falling head method is suitable for fine-grained soils. Answer: A

Explanation

The constant head permeability test maintains a constant hydraulic gradient and allows a measurable volume of water to discharge quickly through highly permeable soil samples. Coarse-grained soils like sand and gravel have high hydraulic conductivity, making constant head measurement accurate and practical. For fine-grained soils with low permeability, the falling head method is preferred instead.

Why the other options are wrong

B) The falling head method is best suited for fine-grained soils with low permeability, such as clays and silts. C) The falling head method is intended for fine-grained soils rather than coarse-grained soils. D) Option A is correct because the constant head method is specifically suited for coarse-grained soils.

Shortcut

Constant Head for Coarse-grained soils; Falling Head for Fine-grained soils.

Common mistake

Confusing the Constant Head method used for coarse-grained soils with the Falling Head method used for fine-grained soils.