Why mass excavate "black cotton soil"? •It exhibits high swelling and shrinkage capabilities. This leads to volume changes in soil resulting in ground movement and potential damage to structures built on it. •Low load bearing capacity due to high clay content. It compresses under high loads thus unsuitable for supporting heavy structures •Low shear strength leading to poor resistance to lateral forces •Maintenance challenges. Differential movement of the soil can cause cracks in walls, floors, a