Study of covered karst soil cave collapse based on PFC numerical simulation
Aiming at the prone area of covered karst collapse disaster in Jiangshan city,a numerical model of covered karst collapse under rainfall conditions was established using the particle flow code (PFC) numerical simulation method. The mesoscopic evolu-tion process of karst soil cave collapse was revealed and the displacement characteristics of soil particles in the overburden layer and the crack propagation during the formation of soil cave were obtained. Additionally,the critical height of soil cave collapse was cal-culated. The results show that,when the system unbalance force,particle displacement and crack number change greatly at the same time,the seepage failure occurs in the soil and the unbalance force is larger,leading to greater degree of soil permeability dam-age. During the development of soil cavity,soil stress changes as follows:stress balance—stress concentration—crack formation—connected surface of crack formation—particle spalling—stress balance. Soil cavity expansion has phases:upward expansion—lat-eral expansion—continuous upward expansion (the maximum critical value of soil cavity height is obtained at this stage)—surface collapse.
万方数据
维普
