# Numerical Simulation and Engineering Application of Temporary Stress Field in Coal Mine Roadway
## 6 Field Application of Shield Tunneling Robot System  
As shown in Figure 10, the shield tunneling robot system consists of a cutting system, temporary support system, permanent support system, ventilation and dust removal system, electro-hydraulic control platform, and transportation system. The cutting system is built into Temporary Support Robot I and connected to the drilling and bolting platform, while Temporary Support Robot II is linked to the electro-hydraulic control platform and transportation system. The entire system moves forward by the alternating push-pull actions of Temporary Support Robots I and II. The cutting system can cut up to 2 m in a single operation, establishing a maximum unsupported distance of 2 m (L1 = 2 m). The total length of Temporary Support Robots I and II is 10 m (L2 = 10 m), which defines the temporary support area as 10 m in length, ensuring that the combined length of the unsupported and temporary support areas does not exceed 18 m (L1 + L2 < 18 m) [99,100].  
Tunnels 112202 and 112204 at the Xiao hoadang Mining Company in Yulin, China, are two parallel tunnels with similar geological conditions. Tunnel 112202 was excavated using a road header, with permanent support installed immediately after excavation, resulting in slow tunneling speed. To prevent delays in subsequent operations, tunnel 112204 was  
Figure 10: Relationship between robot system and surrounding rock (a—unexcavated area; b—unsupported area; c—temporary support area; d—permanent support area; 1—excavating robot; 2—temporary support robot I; 3—temporary support robot II; 4—anchor drilling platform; 5—electro-hydraulic control platform; 6—ventilation and transportation system).  
Figure 9: Roof displacements under different temporary support lengths and unsupported distances.  
exavated using the shield tunneling robot system. The first row of permanent support is positioned 12 m from the working face, enabling excavation and permanent support installation to operate in parallel with the assistance of the temporary support robots, significantly improving tunneling speed and addressing the severe wall spalling at the site, as shown in Figure 11.  
The tunnel roof displacement is monitored using an electronic layer separation instrument, with a monitoring section interval of 100 m and measurements taken daily. As shown in Figure 12, after the operators became proficient in using the tunneling robot system, the daily advance reached up to 56 m, improving tunneling efficiency by nearly 40%. The roof strain between the 112202 and 112204 tunneling faces is quite similar. During the first half of the monitoring period, the roof strain at the 112204 tunneling face was even lower than that at the 112202 tunneling face. This is because the temporary support provides an active support force that exceeds that of rock bolts. Additionally, the roof displacement at the 112204 working face shows a more linear pattern, indicating that the temporary support did not repeatedly support with the roof during movement. This finding partially verifies that the temporary support indeed generates a support stress field in the surrounding rock of unsupported areas, and it also confirms the feasibility of the proposed method of long-distance temporary support following excavation.  
Figure 11: Tunneling face conditions. (**a**) Shield tunneling robot system. (**b**) Road header. (**c**) Tunnel 112204 face roof support condition. (**d**) Tunnel 112202 face roof support condition. (**e**) Tunnel 112204 face sidewall support conditions. (**f**) Tunnel 112202 face sidewall support conditions.