Case Study On The Assessment Of Sinkhole Risk For The Development Of Infrastructure Over Karstic Ground

摘要

Karstic dolomite in the Centurion area of South Africa presents significant challenges tornthe geotechnical engineer. It has been recognised for many decades that sinkholes can occur in the residualrnsoils overlying the Dolomite, but it is not possible to predict their occurrence or their size. Sinkholesrnpresent a significant hazard to infrastructure since they occur suddenly and result in a loss of ground support.rnIn designing the Gautrain Rail Link, routed through the Centurion area, it was necessary to managernthis hazard in a rational way. Adopting the maximum possible size of sinkhole that could occur and designingrnfor this eventuality was considered unrealistic in terms of international practice. This paper presentsrna risk-based approach that was used as part of the design for the section of Gautrain running overrnthe dolomites to demonstrate that sinkhole risks have been made as low as reasonably practicable. Arnquantitative risk assessment was undertaken to model numerically the consequence and likelihood ofrnsinkhole occurrence. This approach enabled the risk from sinkholes to be quantified and was used to helprndefine the design requirements for the infrastructure in respect of this hazard.