Based on the tunnel project of Yunxian-Fengqing Expressway, a feasibility study scheme combining field monitoring and numerical analysis is proposed. The displacement of the palm surface is studied by numerical analysis and practical engineering. After a detailed analysis of the rock displacement variation at different positions in front of the face under different excavation footage, it is found that the excavation footage of the face and the deformation law of the rock in front of the face. The greater the excavation footage is the more unfavorable to the stability of the face. At the same time, it is found that the rock in the face can provide some resistance to prevent the rock in front of the face from moving towards the face and the gravitational potential energy of the rock above the face. The determination method of red line excavation footage and the determination criterion of actual excavation footage on site are proposed. The extrusion phenomenon of the rock stratum in front of the working face in the construction process is discussed, indicating that the red line excavation footage multiplied by the safety factor can better ensure the safe construction of the site.