The material supported by a retaining wall, kept above the horizontal plane at the elevation of the top of the retaining wall, is known as:
Try it first: pick an option, then read the explanation.
Asked in SSC JE 06/06/2024 (Morning)
Detailed Explanation
A retaining wall holds back soil called the backfill, which lies behind the wall up to the level of its top. Anything placed above that level — an extra slope of soil, a road, stacked material, buildings — adds extra load on the backfill and therefore extra pressure on the wall.
Why “surcharge” Is Correct
That extra material or load above the top of the wall is called a surcharge. A uniform surcharge q adds a constant pressure Kaq over the full height of the wall.
| Term | Meaning |
|---|---|
| Backfill | Soil retained behind the wall, up to the level of its top |
| Surcharge | Extra load or material above the level of the top of the wall |
| Infill | Material filling a space (e.g. inside a crib wall or a frame) |
Why the Other Options Are Wrong
- A. infill: Infill is material placed inside a structure or opening, not above the wall top.
- C. backfill: Backfill is the soil retained up to the top of the wall, not above it.
- D. debris: Debris is waste material, not an engineering term for this load.
Key Point
Uniform surcharge q → extra lateral pressure Ka·q, rectangular over the full height.
Key Concepts for Students
- A sloping backfill above the wall is called a surcharged (inclined) backfill.
- Traffic loads behind abutments are often modelled as a surcharge.
- Surcharge thrust Ka·q·H acts at H/2 above the base.
Practice more: this is question 2 in Earth Pressure and Retaining Wall MCQs – Part 1. Try the whole set and check every answer instantly.