Retaining wall detailing — identify the incorrect reinforcement placement statement for stem, toe slab, and heel slab in a cantilever retaining wall.

Introduction / Context:
For cantilever retaining walls, correct placement of reinforcement in the stem, toe, and heel is critical to resist bending induced by earth pressure and soil bearing reactions. This question checks conceptual understanding of where tensile stresses develop in each part so that steel is placed on the correct face.

Given Data / Assumptions:

• Cantilever retaining wall with stem, toe slab (in front of the stem), and heel slab (behind the stem under backfill).
• Backfill exerts lateral earth pressure on the stem.
• Soil pressure under the base acts upward, opposed by weights of the wall and backfill over the heel.
• Reinforcement should be on the tensile face in each member.

Concept / Approach:

A concrete member cracks on the tension side first; steel is therefore placed near the tensile face to carry tension. The stem behaves like a vertical cantilever fixed at the base; the backfill pushes the stem, creating tension on the earth side. The toe slab behaves as a horizontal cantilever subjected primarily to upward soil pressure, causing the top fibers to be in tension. The heel slab experiences combined upward soil reaction and downward weight of the soil-overburden and slab, which typically produces tension at the bottom fibers near the stem support.

Step-by-Step Solution:

Verification / Alternative check (if short method exists):

Draw qualitative bending moment diagrams: stem (cantilever with lateral load), toe (cantilever with upward load), heel (combined actions). The sign of curvature identifies the tension face and confirms steel locations.

Why Other Options Are Wrong:

Option A correctly places stem steel on the earth side. Option B correctly places toe steel at the top. Option D incorrectly asserts all are correct. Option E is irrelevant. The only incorrect statement is that heel steel is at the top (it should be at the bottom).

Common Pitfalls (misconceptions, mistakes):

Assuming all base slabs take bottom steel; ignoring that an upward soil reaction on a cantilever produces top tension on the toe; forgetting the combined action over the heel.

Final Answer:

In the heel slab of a retaining wall, reinforcement is provided at the top of the slab.