Numerical Investigation of the Geomechanics of Sinkhole Formation and Subsidence

Sinkholes are a devastating and widespread geo-hazard which poses a significant threat to the environment, infrastructure, and human lives. Many practices involved in the sinkhole assessment are generally of a qualitative nature and largely based on geological characteristics of the karst terrains. This paper aims to present a quantitative analysis of the deformation involving the various behaviors of the geo-materials and interplay of multiple mechanisms involved during the development of sinkholes. It is primarily focused on the influence of rapid and slow drawdown of water scenarios, studied via a coupled hydromechanical model. Rapid drawdown at a higher rate of head drop causes much higher deformation than the slower drawdown which may lead to fast creation of sinkhole. A parametric study of various properties responsible for the sinkhole development is undertaken which involves influence of cohesion, permeability and ground water flow time. The results shows that the higher permeability and higher ground water flow time causes rapid formation of sinkhole. The resistance to the sinkhole formation in the limestone zone is a function of the tensile strength of the rock while the cohesion and friction angle are responsible for the resistance in the clay soil.