Experimental Investigation of Foundation on Collapsible Soils

Abstract

Geotechnical engineers face serious problems when building on collapsible soils. These types of soil show considerable strength when dry and experience excessive and sudden settlement when inundated. Due to the expansion of modern cities in arid areas, highways and roads may pass through pockets of collapsible soil. If unrecognized, it may cause pumps or deep sinkholes, which leads to traffic accidents and loss of lives. Furthermore, due to the increasing use of water for irrigation and domestic purposes, roads built on collapsible soils may experience uncalculated settlement. This paper presents the results of an experimental investigation of a rigid strip footing on collapsible soils subjected to inundation due to raising the groundwater table. A prototype experimental setup was designed to test these footings on homogeneous collapsible soils, partially replaced collapsible soils with cohesionless material with and without geotextile reinforcement layer at the interface. It is of interest to report that the case of footing on partially replaced collapsible soil with cohesionless material showed slight improvement, while a combination of partially replaced collapsible soil with geotextile layer at the interface showed a significant improvement in reducing the collapse settlement. Design procedure is presented to predict the collapse settlement for a given collapsible potential of the soil, loading conditions, replacement thickness, and strength of the geotextile material used.