## 5 Industrial-Scale Test
### Rock Mass Stability Control Plan  
Grouting modification technology aims to improve the physical properties of the surrounding rock under water-rich conditions, thereby enhancing its overall stiffness and strength. Under high-moisture-content conditions, the surrounding rock is prone to developing microcracks, thereby weakening its compressive and shear strengths. Grouting materials can fill these cracks, restore the integrity of the surrounding rock, mitigate the deterioration caused by water, and enhance the shear and compressive resistances of the rock. Research findings have indicated that grouting effectively slows the rate of crack propagation and significantly enhances the stability and impermeability of the surrounding rock [39]. Combined with full-length anchor-grouting support technology, grouting materials are evenly distributed within the surrounding rock, strengthening the bond between the rock and support structure, thereby enhancing the overall stability of the support system. Through grouting modification, the compactness of the surrounding rock was enhanced, the expansion of microcracks was effectively suppressed, and the likelihood of macroscopic failure was significantly reduced.  
The core objective of encapsulating the surrounding rock is to prevent direct exposure to air, thereby effectively inhibiting weathering. Weathering causes a significant reduction in the surface strength of the surrounding rock, particularly with the decrease in the intermediate principal stress (\(\sigma_{2}\)), which may induce stress imbalance and lead to instability. Studies have shown that under high-moisture-content conditions, the crack initiation and damage stresses of the surrounding rock decrease significantly, making cracks more likely to form and propagate rapidly, thus accelerating macroscopic failure. Encapsulating the surrounding rock can effectively maintain its stress state, prevent stress redistribution caused by weathering, delay the formation and propagation of microcracks, and reduce macroscopic failures, thereby extending the service life of the roadway.  
The advanced grouting reinforcement scheme aims to strengthen the rock surrounding the roadway by injecting grout in advance, thereby enhancing support effectiveness. Owing to the high clay mineral content in the sandstones of the Huaibei mining area and the water leakage phenomenon associated with conventional grouting materials (cement slurry), they are inadequate for reinforcing water-rich roadways. Therefore, grouting materials with high specific surface areas are required. This study improves the original grouting scheme by replacing conventional grouting materials with ultrafine cement-based grouts.  
A full-length anchor-grouting support scheme was designed to enhance the stability of a support structure under special geological conditions. Based on the original support scheme, the timing of the support installation and the parameters of the anchor rods and cables were optimized. Owing to the uncertainty in determining the position of the roof water and the possibility that the roof anchor rods may not penetrate the aquifer, it wasnecessary to promptly grout the surrounding rock after installing the anchor rods and then proceed with the installation of the anchor cables. Additionally, grouted anchor cables were used for full-length anchoring to seal the roof water.