Question

Riprap is provided to
1. protect river banks from erosion by river flow
2. increase the bearing capacity of the soil
3. accelerate the process of consolidation
4. reduce the pore pressure of the soil

Answer 1

Correct Answer - Option 1 : protect river banks from erosion by river flow

Explanation:

Riprap: A permanent, erosion-resistant ground cover of large, loose, angular stone.

Purpose:

(i) To protect slopes, streambanks, channels, or areas subject to erosion by wave action.

(ii) Rock riprap protects soil from erosion due to concentrated runoff. It is used to stabilize slopes that are unstable due to seepage. It is also used to slow the velocity of concentrated runoff which in turn increases the potential for infiltration.

(iii) For design of the riprap, IS : 8237-1985 may be referred. A minimum of 300 mm thick riprap over 150 mm thick filter layer may be provided.