The thickness of base slab of a retaining wall generally provided, is A. One half of the width of the stem at the bottom B. One third of the width of the stem at the bottom C. One fourth of the width of the steam at the bottom D. Width of the stem at the bottom

The correct answer is: A. One half of the width of the stem at the bottom.

The base slab of a retaining wall is a structural element that provides support for the weight of the wall and the soil it retains. The thickness of the base slab is typically one half of the width of the stem at the bottom, which is the vertical portion of the wall that supports the weight of the soil. This ensures that the base slab is strong enough to support the loads imposed on it.

Option B is incorrect because one third of the width of the stem at the bottom is not thick enough to support the loads imposed on the base slab. Option C is incorrect because one fourth of the width of the stem at the bottom is also not thick enough to support the loads imposed on the base slab. Option D is incorrect because the width of the stem at the bottom is not a reliable measure of the thickness of the base slab.

The thickness of the base slab is also affected by the type of soil being retained, the height of the wall, and the seismicity of the area. In general, the thicker the base slab, the more stable the retaining wall will be.