§16§Expansive soils are problematic in nature by virtue of their innate capacity to undergo volume changes when there are changes in moisture regime. These soils swell when they absorb water and shrink when water evaporates from them. So, lightly loaded civil engineering structures founded in these soils are subjected to alternate swelling and shrinkage in rainy and summer seasons. As a result, they experience unsightly cracking. The structural members that get affected are flooring, walls, columns, grade beams, etc. The types of damage are disruption or disintegration of flooring, tensile cracks above doors and above and below window sills and cracks in grade beams and columns. Often, the cost of repair of the structure may exceed the cost of the original structure. Many innovative foundation practices have been devised to counteract the problems posed by expansive soils. These can be grouped into various classes such as mechanical alterations, physical alterations, chemical alterati §16§ons and special foundation techniques. This book discusses in detail the problems posed by expansive soils, the identification methods and the remedies in the form of innovative foundations.
