## 3 Roadway Surrounding Rock Deformation Patterns
### The Impact of Pore Water Pressure on Surrounding Rock Deformation  
Taking the data graph of the displacement of monitoring points under various pore water pressure conditions as an example, when SRC = III, B = 600 m, H = 6 m, and W = 6 m, as shown in Figure 6, the study investigates the impact of pore water pressure on the deformation of surrounding rock. From Figure 6, it can be concluded that:  
(1) After the excavation of the roadway, the deformation of the surrounding rock is characterized by overall convergence towards the interior of the roadway. Monitoring point data show that displacement is greatest at the top of the roadway, likely due to the significant stress release experienced by the top rock, resulting in larger displacements. As the monitoring point location moves downward along the roadway profile, displacement gradually decreases. However, displacement increases at the shoulders (i.e., the connection points between the ribs and the roof). This increase may be due to the structural weakness of the shoulder areas, which are more susceptible to pressure from the surrounding rock mass. Ultimately, displacement reaches its minimum at the walls of the roadway, indicating that  
Figure 5: Surrounding rock stress and plastic zone distribution. (**a**) Vertical stress contour map; (**b**) horizontal stress contour map; (**c**) surrounding rock plastic zone distribution map.  
this part is relatively stable. However, once past the wall, displacement gradually increases towards the center of the floor, indicating that the floor is subject to significant upward pressure, particularly in the center area where larger shear forces may exist. Appropriate support methods for these observed deformation patterns are crucial. First, since the roof bears the greatest sinking pressure, it is recommended to reinforce the roof using a combination of rock bolts, anchors, and shotcrete. Rock bolts provide immediate tensile support, while shotcrete forms a robust protective layer to prevent the fall of loose rocks. Second, due to significant displacement at the center of the floor, it is recommended to use a thicker reinforced concrete slab and, if necessary, apply ground anchors or a pre-stressing system to provide sufficient shear resistance and load-bearing capacity [21; 22]. Finally, since there is a trend of increased displacement in the shoulder area, it is necessary to apply lateral supports such as steel arches and vertical rock bolts to stabilize the sidewalls and reduce lateral deformation.  
(2) An increase in pore water pressure directly impacts the stability of the roadway. When the pore water pressure is less than 3.5 MPa, the increase in roadway displacement is relatively small. This suggests that a low pore water pressure has a minimal impact on roadway stability. However, once the pore water pressure exceeds 3.5 MPa, the displacement of various monitoring points in the roadway sharply increases, especially the shoulder displacement might exceed the top displacement, indicating severe deformation of the roadway. When the pore water pressure reaches 7.5 MPa, the stability of the roadway is severely threatened; there is significant displacement of the roof, severe settlement of the floor, significant convergence of the ribs, and obvious deformation of the roadway profile. To address the impact of pore water pressure, appropriate drainage measures should be taken, such as installing drainage holes and trenches, to reduce the water pressure around the roadway, thereby minimizing the negative impact of water pressure on roadway stability. Additionally, the use of waterproof materials and grouting reinforcement techniques should be considered to block water intrusion and enhance the stability of the surrounding rock [23].  
Figure 6: Displacement curve of monitoring points.