FOUNDATIONS ON COLLAPSIBLE AND EXPANSIVE SOILS: AN OVERVIEW
Keywords:
Expansive soils, collapsible soils, problems, soil improvement methods, re-compaction, soil replacement techniques.Abstract
This study discusses various types of problems associated for constructing engineering projects when the soil consists of collapsible and expansive soils. Collapsible soils and expansive soils causes heavy damages to civil engineering structures like buildings, roads, runways, pipe lines etc., These soils are subject to changes in volume and settlement in response to wetting and drying and resulting in severe damage to structures. Expansive soils in India are popularly known as Black cotton soils. Black cotton soils accounts
about 20% of land area in India and are predominantly located in the Deccan trap covering the states. Most Indian Black cotton soils are rich in Montmorillonite, this mineral is responsible for swell-shrink behaviour of the soil. Collapsible soils make the construction of foundations extremely difficult in its natural state. It may cause high differential movements in structures through collapse settlement. Therefore, to study soil replacement technique taking into consideration geotechnical requirements and cost to achieve the optimum
replacement layer thickness corresponding to minimum cost of foundation works and reduce the collapse settlement under foundation as well
