2D tunneling chart from redistributed 3D principal stress path

The redistributed 3D principal stress path and safety assessment for tunneling are investigated in this paper. Numerical simulations of tunneling were performed, leading to integration of principal stress space with Mohr–Coulomb failure criterion. Different rounds have different three-dimensional redistributed stress within their individual deviatoric planes. These planes cannot be superimposed, making their comparison difficult. However, deviatoric planes representing rounds can be combined one normalized plane whereupon the stress path is plotted, allowing comparison with the cycles. A way creating the normalized deviatoric plane, with stress path therein representing the cycles, is proposed and demonstrated herein. This way clearly delivers the 3D redistributed stress path into a 2D tunneling chart and facilitates to evaluate the tunneling safety.