Research on catastrophic law of delayed gushing water from subsided karst collapse column in the open-off cut blasting excavation

In order to study the temporal and spatial evolution characteristics of the delayed gushing water of subsided karst collapse column during the blasting excavation process of 1035 open-off cut in Taoyuan Coal Mine, based on the permeability mutation characteristics of surrounding rock under the action of dynamic blasting load and fluid-solid coupling, the variation law of stress, displacement, plastic zone, and water inflow were numerically simulated by FLAC^3D, and the influence of the width of the karst collapse column on gushing water was discussed. The research results show that: after the excavation face of open-off cut exceeds the karst collapsed column center by 10 m, the failure plastic zone of open-off cut floor will connect with the influence zone of subsided karst collapse column, resulting in gushing water from the karst collapsed column, and the gushing water has certain hysteresis, suddenness and large amount. At the same time, only when the distance between karst collapsed column impact zone and 1035 open-off cut of Taoyuan Coal Mine is less than 5 m, the open-off cut blasting excavation will cause a gushing water accident. The results can provide theoretical reference for gushing water treatment under similar conditions.