Geotechnical case studies: emphasis on collapsible soil cases

Abstract

Direct exposure of soil to certain atmospheric agents, such as water, can influence adversely or favourably the engineering behaviour of the soil. For instance, saturated and unsaturated/partially saturated soils behave differently, so do soils under seepage and hydrostatic pressures. Many theories in soil mechanics idealise soils as either cohesive or non-cohesive, and this has allowed much research to be done on saturated cohesive soils. However, non-cohesive soils have not received as much attention, apart from recent strength and dilatancy theories, yet in some parts of the world, certain non-cohesive soils pose significant risk to structures built on them. The most problematic examples of such soils are collapsible soils that may not be detected and properly considered in routine ground investigation activities. In this paper some case studies of collapsible soils in the United Arab Emirates are examined to analyse the effect of their collapse on infrastructure and the possible techniques to ameliorate the situation. The case studies include various sites that were found to suffer structural damage traceable to collapsible soils. It is found that in most cases the soil collapse was due to infiltration of rainwater or water from sustained irrigation activities at the surface.