English：

Taking the slope excavation project of the Huangtuling tunnel converted to subgrade as theresearch object, a three,dimensional model of the slope underpassing the tunnel was established using theFLAC3D finite element software. The strain,softening constitutive model was adopted to perform step,by,step excavation calculations for the slope. The influence of the slope excavation on the displacement,principal stress, and safety factor of various parts of the underpassing tunnel structure including the vault,left and right spandrels, left and right sidewalls, and the bottom slab was studied and analyzed. Theresearch results indicate that the deformation, stress levels, and safety factors of various tunnel sections,calculated from the numerical models for the excavation of slopes from the fourth to the eighth level, areall within the permissible limits. Comparing the deformation trend of the tunnel vault obtained fromsimulation with the field monitoring results shows that the measured results are close to the simulationresults. The excavation of the upper slope has a relatively minor impact on the safety and stability of thetunnel structure.