Mechanism of Shallow Soil Cave-Type Karst Collapse Induced by Water Inrush in Underground Engineering Construction

Water inrush disasters are the main cause of karst collapse. In this study, a physical model test was conducted to investigate the mechanism of karst collapse. The formation, expansion, and variation of a soil cave induced by water inrush were studied, including the expansion pattern of soil cavities, the voids between the bottom of the hole, cavity disengagement, wall collapse, and soil cavity expansion. The variation of shear stress in soil under the dynamic change in groundwater level was simulated and analyzed using a finite-difference method. When the groundwater level falls, the expansion and collapse of a soil cave are caused by the concentrated action of shear stress on the arch foot of the soil cave. Results of this study deepen the understanding of karst collapse induced by water inrush in underground engineering and provide guidance for the prevention and control of karst ground collapse. (C) 2019 American Society of Civil Engineers.