Abstract：The model test on mechanism of layered failure within rock mass around deep-buried tunnel is re-analysed. At first，the fracture shape of surrounding rock mass is studied. The failure of the model medium has two patterns：tensile and shear. Stress field of surrounding rock mass is deduced using jagged rock mass model and ultimate strain failure criteria. By comparing with test results，the solution is proved to be correct. It is shown that the interval tension fracture would occur repeatedly under large axial compression stress，which forms the layered failure. The geometry of tension fracture tends to be round gradually. When a new tension fracture takes place，the model is equivalent to a tunnel with support. With the increment of tunnel radial，the supporting force increases rapidly，which makes the layered failure limited to a certain rangeal. The analytical method provides theoretical basis for studying rules of layered failure of rock mass around deep-buried tunnel under different conditions.
