The Minimum Buried Depth of Soil Tunnel Natural Form Arch Based on Twin Shear Strength Theory

To calculate buried depth of the soil tunnel natural form arch based on Mohr-Coulomb strength theory,the intermediate principal stress is not considered.The result is compared with actual situation that there are quite different.Twin shear strength theory is mean to remedy the defect of Mohr-Coulomb strength theory and the intermediate principal stress is considered,which is more realistic.The two theories are used to calculate the actual project.The resuct shows that the calculation based on twin shear strength theory is less than the one based on Mohr-Coulomb strength theory.The result of calculation based on twin shear strength theory is more accurate and the design is safer.