Exploring the Geomechanics of Sinkholes: A Numerical Study of Sinkhole Subsidence and Collapse

The processes of sinkhole development are strongly dominated by the geomechanical characteristics of rock and soil behavior that are complicated by the interaction with chemical reactive processes as well as hydraulic transport processes. Sinkholes formed in soils are generally of a sudden, catastrophic nature, and understanding of cover-collapse sinkholes presents probably the biggest challenge to research communities due to the difficulties in formulating an effective quantitative approach to assess a number of diverse mechanisms behind many intricate processes involved, which are further complicated by a variety of scenarios that can trigger these sinkholes. This paper presents some of the preliminary results of an ongoing research that is aimed to explore a geomechanical modelling approach to understand the process of sinkhole developments. The explicit finite difference program, FLAC is used to model the behavior of geomaterials around a cavity in a potential water drawdown scenario. A parametric study is conducted to examine the effects of different mechanical and hydraulic properties. The results show some key characteristics of sinkhole subsidence and collapse, and demonstrate the feasibility of a numerical modelling approach which must be complimented by theoretical and analytical developments to be able to explore many intricacies and complexities of the mechanisms involved in the mechanisms of cavity growth and propagation.