Author : Khushbu S. Gandhi

Expansive clay soils are extensively distributed worldwide, and are a source of great damage to infrastructure and buildings. The problem with expansive soils has been recorded all over the world. These soils can cause heavy economic losses, as well as being a source of risk to the population. In monsoon they imbibe water and swell and in summer they shrink on evaporation of water there from. The wetting and drying process of a sub grade layer composed of black cotton soil result into failure of substructures in form of settlement and cracking. And because of this alternative swelling and shrinkage, lightly loaded civil engineering structures like residential buildings, pavements and canal linings are severely damaged. It is, therefore, necessary to mitigate the problems posed by expansive soils and prevent cracking of structures. Many innovative foundation techniques have been devised as a solution to the problem of expansive soils. There are numerous soil stabilization techniques for improving the strength of the in-situ soil, and one of the techniques is using chemical additive. Chemical improvement is a time saving method that enables sub grade or sub-base layer and otherwise unsatisfactory materials in-situ to obtain higher density and strength, obviating the need for costly excavation and replacement with borrow material. Surat is located on highly expansive soil. This work is based on an experimental study in the stabilization of an expansive soil in Surat, consisting of the changes of its various properties and its mechanical capacities by the addition of by-products and waste materials of industrial origin such as rice husk ash and marble dust. This may achieve the double objective of reducing the problems of this type of soil, and also of providing a use for the additives, thus eliminating the economic and environmental cost involved in managing them. And also regression analysis for quick prediction of swelling pressure and CBR value of soil with regarding to the other properties of soil is also carried out.

Keywords: Expansive soil, stabilization, swelling, shrinkage, rise husk ash, marble dust.

Article published in International Journal of Current  Engineering  and Technology, Vol.3,No.4(Oct- 2013)