Finding Engineering Solutions in Collapsible Soils, Before and After Construction

Abstract

Two projects undertaken in Saudi Arabia are contrasted and issues that were identified with the founding strata are discussed. In both cases the main condition in the soil was its susceptibility to collapse, specifically under inundation. Interestingly although one deposit was within wind-blown deposits, a form of deposition that is known to potentially give rise to collapsible soils, the other project was on a site underlain by wadi deposits.

The first case study looks at an existing building and how signs of structural distress became evident over a number of years. A forensic investigation was undertaken to determine the causes of this problem. The second case study is focused on a prestigious museum development in Riyadh. Initial investigations suggested that the building could be founded on shallow strip footings, in view of the apparent competency of the underlying wadi deposits. Subsequent in-situ testing identified soil collapse within these strata.

Concluding remarks are provided on investigation techniques to be used to identify these types of problem soils and the value of engineers using observational skills, rather than focusing on the relatively indiscriminate use of routine field and laboratory testing.