From the standpoint of engineering, the change law of parameters has great application value to instruct the design and construction of tunnels.
Table 1 shows the numerical results calculated with the proposed failure mode with respect to the parameters of A1, B1. Table 1 illustrates the influence of uniaxial compressive strength in upper stratum, σc1, the ratio of upper collapse height to the whole height, n0, and the mechanical parameters of upper rock layer, A1, B1, on the overall size of collapsing blocks, and the rock masses are characterized by two groups of mechanical parameters.