Simulation Study On Electrical Monitoring Test Of Covered Karst Collapse

Due to the influence of climate,environment and geology,karst is developed in the south of China.In recent years,with the development of economy and technology in karst areas,the acceleration of urbanization,and the destruction of the environment by humans,karst collapse disasters have occurred frequently.The karst collapse has severely restricted the economic construction of the karst area,destroyed engineering buildings,and threatened the safety of people’s lives and property.Therefore,there is an urgent need for a method to effectively predict karst collapse disasters.However,due to the concealment of karst collapse in space,the suddenness in time,and the complexity of the formation mechanism,conventional monitoring methods are not effective.In this paper,the electrical method is used to monitor the covered karst collapse.Through numerical simulation and physical model test,the numerical model and indoor physical model of the covered karst collapse process are established to analyze the reliability and applicability of the electrical method monitoring.The completed research work and progress are as follows:(1)According to the actual engineering situation,the Ag I software is used to build the numerical model of karst collapse with single uniform medium overburden,and the forward model of different stages in the process of karst collapse is established.The geoelectric response characteristics of different stages are obtained through forward and inverse calculation.By processing the inversion data of the numerical model with the abnormal coefficient,the position and size of the resistivity change in different stages of karst collapse can be further obtained.The purpose is to get the geophysical characteristics and changes in different stages of karst collapse.(2)Building indoor physical model and establish the electrical monitoring system to monitor the collapse process of the physical model,record the different resistivity response and spontaneous potential in the whole process,and process the monitoring data by professional software.The results show that the monitoring results of the physical model test are basically consistent with the numerical simulation results,and the spontaneous potential results are combined with the actual situation of the model Spontaneous potential mutation occurs after the formation and collapse of chambers.The natural potential curve and apparent resistivity profile can reveal the location and approximate time of soil chamber development.