In the case of a counterfort retaining wall, the toe acts as a
- ASimply supported slab
- BCantileverCorrect
- CContinuous slab
- DNone of the above
Solution
Concept
Structural behavior of retaining wall toe
Formula
NONE
Step-by-step solution
1. A counterfort retaining wall features a vertical stem, toe slab, heel slab, and counterforts. 2. Counterforts connect the heel slab and vertical stem, making them act as continuous slabs. 3. The toe slab projects forward from the stem and is subjected to upward soil pressure, thus acting as a cantilever slab. Answer: B
Explanation
The toe slab of a counterfort retaining wall projects horizontally outward from the front face of the vertical stem. Because it is fixed at the base of the stem but unsupported at its outer edge, it experiences net upward soil pressure from the ground below. This structural boundary condition causes the toe slab to function and resist bending as a cantilever.
Why the other options are wrong
A) Simply supported slab behavior is seen in the vertical stem slab between counterforts, not the toe. C) Continuous slab behavior applies to the stem or heel slab spanning across counterforts. D) Option B is correct because the toe slab projects forward as a cantilever.
Shortcut
In counterfort walls, the toe acts as a Cantilever, while the stem and heel act as continuous slabs.
Common mistake
Assuming the toe slab acts as a continuous slab like the stem rather than a cantilever.
Correct answer: B) Cantilever