Stratum deformation caused by different tunnel excavation steps

Based on the stochastic medium theory,the method of stratum deformation calculating considering time-space effect was studied.Multiple working face could be taken into account in tunnel construction at the same time.Then the time-space rules of the stratum deformation caused by different excavation steps,such as face excavation,back excavation and longitudinal excavation,were discussed.Under the face excavation,the positive curvature and tensile deformation on ground surface were about twice those under the single excavation,and it was harmful to the architecture on the ground surface around the tunnel.The longitudinal distance of different excavation steps should be larger than the influence radius of excavation.The obtained results achievement could provide scientific basis for controlling the stratum deformation caused by tunnel construction and protecting the safety of the buildings and pipelines around the tunnel.