## 3 Results and Discussion
### Analysis of Rock Formations in the Area of Influence
#### 3.1.2 von Mises Stress Response
The von Mises stress change at the measurement point exhibits three stages, which are slightly rising (S2 and S3), slightly falling (S4), and slowly rising (S5-S10); the D3 Von Mises stress change at the measurement point exhibits four stages, which are slightly rising (S2), slowly rising (S3 and S4), rising (S5- S8), and stabilizing (S9-S10); and the von Mises stress changes in the D4 and D5 measurement points can be divided into the following five stages: slightly rising (S2), slowly rising (S3), rapidly rising (S4), rising (S5-S7), and stabilizing (S8-S10). The MS4 measurement points can be divided into the following three categories: D1-D3 measurement points with low stress reduction and low perturbation area, D4 measurement points with medium stress reduction and medium perturbation area, and D5 measurement points with strong stress rise and strong perturbation area. The D1-D3 measuring points' von Mises stress change manifested as the following three stages: a slight rise (S2-S6), a rapid decline (S7 and S8), and being stable (S9-S10); the D4 measuring points' von Mises stress change manifested as the following four stages: a slight rise (S2-S6), a decline (S7), a rapid decline (S8), and a slight increase (S9-S10); the von Mises stress change at the D5 measurement point is characterized by the following five stages: slightly rising (S2-S6), rapidly rising (S7), slightly falling (S8), slightly rising (S9), and stabilizing (S10). The MS5 profile measurement points can be divided into D2 and D3 measurement points with low disturbance, D1 and D4 measurement points with medium disturbance, and D5 measurement points with strong disturbance (S10); the D4 measuring point von Mises stress change shows three stages of slight rise (S2-S6), rapid rise (S7-S9), and slight rise (S10); the D5 measuring point von Mises stress change shows four stages of slight rise (S2-S6), rise (S7), rapid rise (S8-S9), and slight rise (S10). Side wall measurement points: the change rule of von Mises stress at the measurement points of the left and right side wall profiles is consistent, the change in von Mises stress at the measurement points of the tunnel structure is prominent, and the change in von Mises stress at the other measurement points has similar values. The change in von Mises stress at the U1 measurement point of the MS1 profile exhibits a slow decline (S2), a rapid decline (S3 and S4), a rapid rebound (S5-S7), and a slow recovery (S8-S10); the MS2 profile U1 measurement points' von Mises stress change shows a slow decline (S2), a rapid decline (S3 and S4), a slow decline (S5), and a slow recovery (S6-S10); the MS3 profile U1 measurement points' von Mises stress change shows a slow rise (S2) and a slow decline (S3); the MS5 profile's U1 von Mises stress change manifested as a slow rise (S2-S6), a slow decline (S7), a rapid decline (S8-S9), and a slow recovery (S10); each profile U2-U5 measurement points' von Mises stress change law is similar to that of the U1 measurement point, with the range of the stress value being smaller and the change stage is slow. Comprehensive analysis concludes that the existing tunnel roof and side wall points' von Mises stress disturbance mainly occurs in the tunnel structure area. The distance between the excavation surface and the typical profile determines the trend of stress change at the measuring point, which is characterized by a stress rise when the distance is far away and a stress fall when the distance is close, and can be classified into the following four types: micro, slow, normal, and fast. The sensitive distance of roof stress disturbance ranges from 2 to 4 excavation data extraction time steps, i.e., in the 40-80 m range; the sensitive distance of side wall stress disturbance ranges from 2 to 3 excavation data extraction time steps, i.e., in the 40-60 m range.