Analytical and numerical study of dolomite sinkholes in Centurion South Africa

Includes bibliographical references.Sinkholes encompass the withdrawal of shallow sediment into deep hollow compartments located in karstic stratum. These subsequent surface openings associated with karst geology have inhibited multiple infrastructure developments. Sinkholes are triggered by the alteration of the existing groundwater level which erodes weathered altered dolomite (WAD) residuum into karst cavities. Substantial literature has explored the stability of sinkholes, with reliance on limit analysis and empirical data, to quantify the strength of the porous karst residuum. In this study, the appraisal of sinkhole propagation was facilitated with the geological data acquired along the Gautrain route through Centurion, South Africa. Sinkhole development was analysed through analytical theories and the application of numerical methods. The analytical study conceptualized the ‘angle of draw’ of dolomite overburden layers into cavities, with Terzaghi’s arching in soil equation. The analytical results illustrated constant vertical drawdown in the WAD and incremental cavity propagation in the frictional chert residuum