Sinkholes pose a major threat to environment, infrastructure, and human safety. They can develop via a cluster of inter-related processes, including bedrock dissolution, rock collapse, soil washing away, and soil collapse. Current practices involved in the sinkhole hazard assessment are generally of a qualitative, empirical nature and largely based on geological characteristics of the karst terrains. This talk aims to present a quantitative analysis of the interplay of multiple mechanisms involved during sinkhole development. The dominant mechanism behind sinkholes formed in rocks is the dissolution of soluble karstic rocks. Dissolution process may be enhanced by potentially aggressive groundwater acidity and the presence of caves or fissures. Specific dissolution rate of the constituent mineral (limestone or dolomite) and the surface area available for reaction are related via a chemo-mechanical coupling with the consideration of the damage-enhanced dissolution mechanism. The second part of the analysis explores the cover collapse type of sinkholes in which the critical mechanism is the growth and upward propagation of cavity. A strain-softening constitutive model is used to describe the strength evolution dependent on accumulated plastic deviatoric strain and erosion progression of soils around the cavity. The numerical results demonstrate the feasibility of expanding classical geomechanics to address intricate, often coupled processes in sinkholes.

Dr. Hu is an Associate Professor in the Department of Civil and Environmental Engineering at the University of Toledo. He received his B.E. in Structural Engineering from Tongji University, Shanghai, China, and M.S. and Ph.D. in Geotechnical Engineering from Duke University. His present research interests are primarily in geohazards and energy geotechnics.