Which of the following types of soil is known for its high load-bearing capacity and stability, making it ideal for the construction of foundations?
Try it first: pick an option, then read the explanation.
Correct answer: B. Sandy soil
Asked in SSC JE 05/06/2024 (Morning)
Detailed Explanation
A good foundation soil should be strong in shear, settle little, and not change much with moisture. Coarse-grained soils usually do this better than fine-grained or organic soils.
Why “Sandy soil” Is Correct
Sandy soil has large grains with frictional strength. Water drains out quickly, so settlement is small and finishes during construction, and it does not swell or shrink. Well-compacted sand therefore has good bearing capacity and is the best of the four options.
| Soil | Bearing behaviour |
|---|---|
| Sand | Good; drains freely, small quick settlement |
| Silt | Fair to poor; loses strength when wet, prone to frost and piping |
| Clay | Variable; low permeability, long-term consolidation settlement, may swell/shrink |
| Peat | Very poor; highly compressible organic soil |
Why the Other Options Are Wrong
- A. Silty soil: Silt has moderate strength, loses strength when wet and can settle and erode.
- C. Peat soil: Peat is organic and highly compressible — one of the worst foundation soils.
- D. Clay soil: Clay can settle for years by consolidation and may swell and shrink.
Key Point
Sand and gravel: good foundation soils. Peat and organic soils: worst.
Key Concepts for Students
- Loose sand still needs compaction before use.
- Saturated loose fine sand can liquefy in earthquakes.
- Organic soils are usually removed and replaced before building.
Practice more: this is question 6 in Shallow and Deep Foundation MCQs – Part 1. Try the whole set and check every answer instantly.