Influence of water level dropping rates on the collapse of karst soil caves
The change of water-gas pressure caused by the rise and fall of water level will lead to the collapse of karst soil caves.In this study,we combined the physical model test and FLAC3D numerical simulation to simulate the soil cave collapse caused by water level fluctuation under the same water supply rate and different drainage rates.Besides,we also analyzed the influence of different drainage rates on the variation of water-gas pressure,soil pressure of the overlying soil layer and deformation of soil caves during the fluctuation.We also established the relationship between water-gas pressure and variables such as drainage rates,overburden deformation and cave,and put forward the action law of water level fluctuations on the collapse of soil cave.The results show as follows.(1)The influence of drainage rates on the variation of water-gas pressure is basically the same,but with different degrees.The change degree and response time of water-gas pressure are positively correlated with the drainage rate.(2)The change of overburden deformation and soil pressure is positively correlated with the change of water-gas pressure,but with different influence degrees.The drainage rate can only accelerate the change degree.(3)Degrees of deformation and collapse of soil caves are caused by comprehensive factors.The speed of the drainage rate and the number of water level fluctuations influence the changes of water-gas pressure in different degrees in soil caves and also influence the soil deformation caused by water level fluctuations.(4)The numerical simulation results are basically consistent with the results of laboratory model test.These results provide important theoretical support for further research on the laws of hydrodynamic factors affecting karst collapse and provide a basis for rational prevention and prediction of karst collapse.
soil cave collapsephysical model testFLAC3D numerical simulationdrainage ratewater level fluctuation
万方数据
维普
