Question

Consider the following statements:
1. Each year, black cotton soil appreciably shrinks during dry season and swells during rainy season. This alternate cycle of shrinking and swelling causes severe stresses in structures supported directly by such soil.

2. Black cotton soil contains predominantly a clay mineral called kaolinite, which is responsible for causing appreciable shrinking and swelling.

3. Shrinking and swelling of black cotton soils are observed only upto a certain depth below the ground level. Below that level, there is neither shrinking nor swelling.

Which of these statements is/are correct?

• A. 1, 2 and 3
• B. 3 only
• C. 2 and 3 only
• D. 1 and 3 only

Answer 1

The correct option is D 1 and 3 only

(d)
Black cotton soils contains predominantly a clay mineral called montmorillonite, which is responsible for causing appreciable shrinking and swelling. Clay soils containing other clay minerals do not exhibit the volume change characteristics to the same degree as those containing montmorillonite mineral.