Limit Analysis of Collapse Mechanisms for Tunnel Roofs Subjected to Pore Water Pressure: A Numerical Approach

Figure 6

Effect of material parameter B of Hoek–Brown criterion on collapse mechanisms. The parameters are A = 0.35, σ_c = 3 × 10⁴ kPa, σ_t = σ_c/100 = 300 kPa,  − h_t = 16.68 m, r = 3.75 m, C = 50 m, and γ_sat = 28.33 kN/m³.