# Stability Analysis of Roadway Groups under Multi-Mining Disturbances
## 4 Numerical Simulation of Deep Well Roadway Group Disturbance Effect
### Influence of Roadway Excavation Disturbance  
In the process of excavating a group of roadways (distance 30 to 50 m), the stress redistributes after the roadway is excavated, and there is a mutual influence between the roadways. The stress distribution, displacement distribution, and plastic zone distribution of the surrounding rock of the roadway after excavating the roadway can reveal whether there is a mutual disturbance in the roadway group. The mutual disturbance between the roadways complicates controlling of the surrounding rock of the roadways.  
Figure 9 shows the vertical stress distribution of surrounding rock after excavating the roadway group. There are four main roadways at the level of \(-740\) m in the south wing. The distance between the track roadway, the ventilation roadway, and the belt conveyor roadway is 30 m, and there is a slight mutual disturbance between the roadways. The distance between the belt conveyor roadway and the auxiliary transportation roadway is 50 m, and there is no mutual disturbance.  
Figure 10 shows the surrounding rock displacement cloud diagram after driving the roadway group. After the roadway group is mined, the maximum deformation of the surrounding rock of the roadway is about 9.8 mm under the design support parameters. The deformation of the surrounding rock of the roadway can be controlled for values below 9.8 mm. However, in the later stage of the roadway under the influence of deep high ground stress, the creep deformation increases the deformation of the roadway surrounding rock, and thus it is not considered here.  
Figure 11 shows the plastic zone distribution of the roadway surrounding rock after excavating the roadway group. The surrounding rock of the roadway has plastic deformations under the condition of stress concentration. For the deep roadway group, the surrounding rock of the roadway has a different distribution of plastic zone under different rock strata conditions. The ventilation roadway is used as a coal seam roadway, and the roof and floor of the roadway have a larger plastic zone. In particular, the floor is mudstone, the depth of the floor plastic zone is about 3.0 m, and the plastic failure range is large, which is difficult for roadway control. In the subsequent roadway treatment process, it is necessary to ensure the quality of the roadway floor support and stability of the floor surrounding rock. For the study of the four roadways, the plastic zone at the top and bottom  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters, Unit** & **Rock Bolt** \\ \hline Elastic modulus, GPa & 200 \\ Poisson’s ratio & 0.3 \\ Diameter/thickness, mm & 22 \\ Pre-tensioning, kN & 100 \\ \hline \hline \end{tabular}
\end{table}
Table 5: The support materials used in the numerical simulation.  
Figure 9: Vertical stress distribution of surrounding rock behind excavation of roadway group.  
of the roadway is about 2.5 to 2.6 m, and long bolts are needed to control the surrounding rock of the roadway. The design of a 3 m long anchor rod can realize an anchoring section in the stable rock formation, a long anchor rod, and anchor cable cross-border support, and construct deep and shallow load-bearing rings.  
From the stress distribution, deformation, and plastic zone distribution characteristics of the surrounding rock in roadway group excavation, it is determined that the full plastic failure range of the roadway is large, and thus a 2.4 m bolt support is adopted. The anchoring section is within the range of broken surrounding rock, and there is no stable fulcrum to build a deep and shallow load-bearing ring. The surrounding rock of the roadway was repeatedly damaged and repaired. The use of 3.0 m bolts can realize the construction of deep and shallow load-bearing rings, which is a scheme for roadway stability control. Since the simulated model domain is relatively small, the goat fails to bend and sink after the working face; however, the influence of this effect on the simulation results is insignificant.