Analysis of Mechanical Response of Tunnel Excavation Near Entrance

In the tunnel excavation process,the structure of rock and soil mass changes and the stress adjusts accordingly,which will consequently cause the deformation or damage of the rock and soil mass surrounding the tunnel. Taking long single arch tunnel of a two-way,twin-tunnel highway as an example,the paper uses the finite element software COMSOL to build the two-dimensional finite element model of the cross section of a tunnel entrance section,and furtherly studies the mechanical response of rock mass during excavation of tunnel near the semicircular arch cross-section entrance under the condition of soft rock overlying strata. In the process of tunnel excavation,the stress and deformation range near the excavation area are the important parameters to estimate the tunnel reinforcement,and provide the basis for the excavation and support of tunnel entrance section,which guides the tunnel construction.