Abstract:

On basis of the irrationality of the material nonlinearity and geometry nonlinearity considered in the calculations of the numerical analysis performed to simulate the stepbystep excavation of the tunnels by means of superposition method, the article proposes a spatial opposite loading method for the numerical simulation of the excavation of tunnels by finite element method. According to the excavation steps, appropriate proportions of the pressing stresses acting on the excavation face are converted into loads in opposite directions so as to simulate the stress releasing of the surrounding rock mass during tunnel excavation. By means of the presented method, real and convenient simulations of the consecutive variations of the forces of the structures and surrounding rock masses during the tunnel excavation can be achieved and nonlinear analysis can be made without difficulty.