## 6 Stability Control and Assessment of Gob-Side Entry
### Stability Assessment of Gob-Side Entry  
1. Displacement change in surrounding rock on roadway surface  
The displacement data obtained from the observation station arranged on site are collated, and the displacement changes in the surrounding rock on roadway surface are shown in Figure 17. After the monitoring, the site survey was carried out on 1331 (1) track roadway in Zhujidong Mine, and the on-site condition of surrounding rock on the roadway surface was shown in Figure 18.  
As can be seen from the figure, the deformation rate of the surrounding rock on the surface of the track roadway is the largest within about 10 days of the formation of the roadway. At this stage, it is mainly due to the fact that the mining stress generated by the formation of the roadway has not reached equilibrium. Within 10 to 15 days of the formation of the roadway, the displacement growth rate of the surrounding rock on the surface of the roadway gradually decreases until it tends to be stable, and the disturbance effect of roadway excavation on the observation point is becoming less and less; About 20 days after the formation of the roadway, the displacement of the surrounding rock on the surface of the roadway tends to be stable and basically does not change. During the monitoring period, the maximum displacement of the top and bottom plates is 86 mm, the maximum displacement of the solid coal side of the roadway is 50 mm, and the maximum displacement of the coal pillar side is 70 mm. The displacement of the coal pillar side of the roadway is greater than the displacement of the solid coal side. It can be seen from the on-site conditions of the track roadway in the later stage that the overall control effect of the roadway surrounding rock is good. Figure 16: Layout map of stations. Figure 17: _Cont._  
2. Separation of the roof of the roadway  
The roof separation of 1331 (1) track roadway was monitored by a 4-point separation meter, and the depths of observation points 1#-4# were 2.7 m, 4.0 m, 7.3 m, and 8.0 m, respectively. The separation of the roof of the track roadway was shown in Figure 19.  
Figure 17: Change in displacement of surrounding rock on the roadway surface. Figure 18: The on-site condition of the roadway. Figure 19: Roof separation curve. after the track roadway was completed. After that, the separation amount tended to be stable and basically did not change. The maximum separation amounts of observation point 1# and 2# at the observation station 1# were 14 mm and 22 mm, respectively, and the roof separation amount at the observation station 1# was small. The maximum separation amounts of observation point 1# and 2# at the observation station 2# were 10 mm and 18 mm, respectively, and the roof separation amount at the observation station 2# was small. The maximum separation amounts of observation point 1# and 2# at the observation station 2# were 18 mm and 18 mm, respectively, and the roof separation amount at the observation station 2# was small. The maximum separation amounts of observation point 1# and 2# at the observation station 3# was small. The monitoring data of the roof of 1331 (1) track roadway show that the roof separation amount is small, and the surrounding rock of the roof is relatively stable. 3. Analysis of load on anchor bolt and cable  
During the excavation of 1331 (1) track roadway, the load conditions of some anchor bolts and cables on the coal pillar side, solid coal side and the roof of the roadway is monitored, and the data are summarized and sorted to obtain the stress changes in the anchor bolts and cables, as shown in Figure 20.  
As can be seen from the above figures, in the early stage after driving the track roadway, due to the influence of driving disturbance and residual stress of the adjacent gob area on the surrounding rock of the roadway, the load on anchor bolts and cables gradually increased within about 12 days, and then the load tended to be stable and basically did not change.