Calculation of Surrounding Rock Pressure on Shallow Buried Tunnel Using Linear and Nonlinear Failure Criterion

Based on Terzaghi failure mode, calculation method of surrounding rock pressure on shallow buried tunnel was established using linear and nonlinear failure criterion, the modified Terzaghi theory which was extended to complex strata and the corresponding recurrence formulas for calculating vertical earth pressure was obtained by theoretical derivation. The surrounding rock in fractured zone of tunnel side wall was analyzed as isolated body by limit equilibrium method, and the explicit calculation expressions of horizontal earth pressure of shallow buried tunnel was obtained. Case analysis indicates that this method is feasible. And then, the effect of lateral pressure coefficient of overlying strata and nonlinear coefficient to surrounding rock pressure with linear and nonlinear failure criterion was further studied, the results show that the surrounding rock pressure decreases notably with lateral pressure coefficient of overlying strata increasing and decreases slowly with nonlinear coefficient increasing, and the effect of nonlinear coefficient to horizontal earth pressure is somewhat large.