Correct Answer - Option 2 : Soil cement lining
Concepts:
Canal linings are classified into two types based on the surface of lining:
- Earthen type lining
- Hard surface lining
1. Earth Type Lining: They are two types: Compacted Earth lining and Soil Cement Lining
A. Compacted Earth Lining: In this earth material available near the construction sites is used and compacted in order to reduce the size of voids in soil by displacing air and water which in turn leads to increase in the density, compressive strength and shear strength of the soil and reduces permeability and seepage losses.
B. Soil Cement Lining: In this sandy soil and cement are mixed in some definite proportion and mixture used for canal lining. The cement content should be minimum 2-8% of the soil by volume.
2. Hard surface lining: This is sub-divided into four types:
A. Cement Concrete Lining: Concrete linings are suitable for both small and large channels and both high and low flow velocities.
B. Brick Lining: In case of brick lining, bricks are laid using cement mortar on the sides and bed of the canal. After laying bricks, smooth finish is provided on the surface using cement mortar.
C. Plastic Lining : In this, different types of plastic membranes such as Low density poly ethylene, High molecular high density polythene, Polyvinyl chloride are used for canal lining.
D. Boulder Lining: The different sizes of stone blocks having irregular gradation are laid with mortar for canal lining.
