[Manish Jain]

For foundations in Black Cotton (BC) soil, the key issue is not simply low bearing capacity—it is the shrink–swell behaviour of expansive clay. Will discuss here a case with BC soil extending to 10 m depth, and compares stabilized soil/macadams with under-reamed piles.
Why Black Cotton Soil is problematic
BC soil:

• Swells when it absorbs moisture
  
• Shrinks and cracks when it dries
  
• Can produce differential movement below foundations.
  
• Light structures can actually be particularly vulnerable to heave; the reference notes this observation for single-storey buildings.
  

for more detail .... https://frontdesk.co.in/building-constru...-in-india/