Forecasting of instability zones induced by creep fracture of tunnel rockmass

The rockmass around the underground tunnel usually has one suspending side,which may lead to creep under biaxial stress.As time goes by,it may bring serious contraction distortion to the tunnel,namely,creep fracture damage.The experiments were based on the geologic information of Baijiao coal Mine.A 3D structural model was established by use of 3D-σ finite-element software.The heading and bench method was adopted for the tunnel.Then the two-step processing of instability induced by the creep fracture of rockmass was used to analyze the evolution features of the plastic zones caused by the creep fracture.The conclusion might be used to offer theoretical references to the designe of tunnel supports.