Question

Cohesive soils are ____

• A. Good for backfill since they exert low earth pressure
• B. Good for backfill because of their high shear strength
• C. Poor for backfill because of large lateral earth pressure
• D. Good for backfill as density is low

Hint:

Preferred backfill material: \[ \boxed{ \text{Free-draining granular soils (sand and gravel)} } \] Avoid cohesive soils due to poor drainage and higher earth pressure.

Answer 1

The Correct Option is C

Step 1: Recall the properties of cohesive soils. Cohesive soils (such as clay) have poor drainage and can develop significant lateral earth pressure, especially when saturated.

Step 2: Identify the suitable statement. Therefore, cohesive soils are generally not preferred as backfill material. Hence, \[ \boxed{\text{Poor for backfill because of large lateral earth pressure}.} \] Therefore, \[ \boxed{(C)} \] is the correct answer.