Numerical simulation on safe thickness in tunnel with a karst cave filled with high pressure water in Xuyong to Dacun railway

Karst cave with high pressure water in tunnel is taken as a study case,some karst tunnel belonging to the railway from Xu Yong to Da Cun is taken as background,the method called numerical simulation is applied,comprehensive and systematic simulation analysis is made,then the stability of surrounding rock of the tunnel in the condition of different water pressures and different classifications of surrounding rock is studied.As a result,the safe thickness is determined,and the conclusion that water pressure,compared with classification of surrounding rock,is the main factor influencing safe thickness is drawn,which can be taken as a reference to safe construction as well as hazard prevention and early warning.