Study On Stability Of Soil Cave Roof At Thick-covered Karst Zone In The Yinde Section Of Passenger Dedicated Railway From Wuhan To Guangzhou

Karst collapse is one of the significant geo-disaster in the thick-covered karst developing zone, which threats and affects both production and living of human being, especially in transportation.The process of karst collapse of thick-covered type are soil cave formation, soil cave expanding and ground collapse, among which the fluctuation of groundwater level is the most active factor. Through the process, groundwater level has played a vital role, on the other hand, dynamic load reduces the shear strength by disturbing the structure of the soil. Therefore, the balance of soil has been destroyed and collapse accelerated.Based on basic geological background along railway and field investigation, this paper has mechanically simulated the stability of soil cave roof under groundwater flutuation. Furthermore, stability of soil cave roof has been simulated by method of dynamic load. The requried results are as follow:(1) According to the regular patern and formation condition of karst collapse, the effected factors and general geological model have been investigated;(2) The formula of critical height of soil-hole and mechanical model of collapse have been set up using the equilibrium arch theory ofМ·М·Протодьяконовand limit equilibrium theory, which have evaluated the typical collapse in this zone. The result fits the pratical situation;(3) Ultimate bearing capacity of soil cave roof under multiple conditions has been abtained by semilog method through the research of stress and deformation feature and evolution in plastic zone;(4) The impact of depth, span and soil propertise on stability under varied dynamic load has been studied through multi-program.