NUMERICAL MODELING OF THE STABILITY OF SOIL IN KARST TERRAIN

An estimate of the hazard or likelihood of sinkhole development is important during the construction of infrastructure such as highways, bridges, building foundations, and landfills in karst terrain. Often, the stability of the residual soil is compromised as the thickness of the residuum is reduced during excavation. In this study, numerical stability analyses were performed by the Finite Element Method (FEM), where the residual soil was assumed to be represented by a Mohr-Coulomb model. It was assumed that a soil void exists in the residual soil above solutioned limestone, and the stability was investigated for a range of void diameters, soil thicknesses, and soil strength properties. The results were summarized in a design chart in terms of dimensionless stability numbers and compared with analytical solutions from the literature. Such stability numbers can be useful to estimate the stability of a given site based on the expected thickness of the soil overburden and the likely range of anticipated soil void diameters.