Controlling the stability of deep high-stress fractured soft rock roadways is a key scientific issue in mining engineering. Using the south wing return-air roadway at the - 650 level of Yangcheng Coal Mine as the engineering background, this study performed mechanical property tests, mineral composition analysis, and in-situ stress tests on the surrounding rock. It further investigated the failure mechanisms and control strategies from the perspectives of lithology and stress environment. The results indicate that the main causes of large deformation in the roadway are: high in-situ stress, high clay mineral content (> 50%) in the soft surrounding rock, superimposed mining-induced stress, and the lack of coupling between the support structure and the surrounding rock. We proposed an active-passive full-space collaborative control technology consisting of concrete-filled steel tubular supports, bolt-mesh-shotcrete, and surrounding rock grouting. Using similar simulation, we investigated the stress distribution of the surrounding rock, deformation characteristics of support structures, load-strain response of supports, and displacement evolution of the surrounding rock under coupled static-dynamic loading. The results demonstrate the excellent bearing performance of concrete-filled steel tubular supports under high static loads and strong disturbances. Field monitoring results show that the maximum roof subsidence was 51 mm, floor heave 106 mm, and side convergence 77 mm. These data indicate that the deformation and failure of the surrounding rock have been effectively controlled. This study provides a theoretical basis and technical support for surrounding rock control in deep, high-stress, fractured soft rock roadways.
To address the large deformation control problem of surrounding rock in high-stress roadways subjected to multiple disturbances, the 112 transport crosscut of Laoyingshan Coal Mine in Guizhou Province was taken as the engineering background. The deformation and failure mechanism of surrounding rock in disturbed high-stress roadways was investigated by theoretical analysis, numerical simulation, drilling cuttings testing and field monitoring. A three-dimensional precise borehole pressure-relief control technology based on the identification of the stress peak zone was proposed, and the effects of key pressure-relief parameters and engineering application were analyzed. The results show that the superposition of repeated mining in multiple coal seams, adjacent roadway excavation and concentrated coal-pillar stress causes continuous redistribution of surrounding-rock stress. The migration of peak stress toward deeper zones and the expansion of the plastic zone are the dominant factors inducing non-stationary plastic large deformation of the roadway. The proposed precise three-dimensional borehole pressure-relief technology reconstructs the stress-transfer path of the surrounding rock, transfers high stress from the shallow anchorage-controlled zone to the deeper stable zone, and preserves a load-bearing elastic structure in the shallow zone, thereby forming a coordinated control mode of "shallow load bearing and deep pressure relief". Parameter analysis indicates that borehole diameter, depth and spacing are strongly coupled. An excessively small diameter is insufficient to form an effective pressure-relief zone, whereas an excessively large diameter may damage the anchorage zone. The borehole depth should match the stress peak zone, and the spacing should ensure the continuity of the pressure-relief zone. In the field application, the stress peak zone of the 112 transport crosscut was identified by the drilling cuttings method, and a pressure-relief scheme with a borehole diameter of 133 mm, spacing of 2 m, depth of 38 m on the east side and 32 m on the west side was adopted. Field monitoring and numerical results show that the plastic zone was significantly reduced after pressure relief, and in the left rib section adjacent to the New First Mining Area haulage rise, specifically the 0-33 m section, the deformation reduction reached 82.23% after pressure relief. Borehole imaging results were consistent with the identified stress peak zone. The research results provide a reference for surrounding-rock stability control in disturbed high-stress roadways.
Bo Zhou, Zhenhong Xu, Shaobing Lv et al.· Scientific Reports· 0 citations
To address large deformation and support failure in deep, high-stress soft-rock roadways, this study investigates the - 810 m track main roadway of Pansan Coal Mine using fiber Bragg grating three-dimensional stress monitoring and borehole fracture observation, combined with FLAC3D numerical simulations. Results show that the maximum principal stress gradually transfers to the deep surrounding rock with increasing roadway distance, while the shallow rock undergoes continuous unloading, promoting plastic zone expansion and eventual instability. Timely reinforcement of the shallow surrounding rock is critical to forming an integral load-bearing system with the deep rock mass. The spatiotemporal effect of principal stress evolution is identified as the fundamental cause of roadway failure, providing theoretical and practical guidance for deep roadway support design.
During coal mining in western China, soft rocks with low strength, poor cementation, and a tendency to disintegrate upon water exposure are often encountered. This makes bolt support unable to maintain long‑term roadway stability, resulting in severe roadway deformation and failure. To solve this challenge, this manuscript combines theoretical research, numerical simulation, and field measurements. Firstly, the characteristics of weak cementation and low strength of weakly cemented soft rock were obtained through experiments. Combined with the field‑monitored features of large‑scale roof fracturing and failure in gob‑side roadways, the support failure mechanism was revealed: poor support effectiveness caused by surrounding rock fracturing in the anchored section of roof bolts. Secondly, the tangential stress around the rectangular roadway was obtained through theoretical calculation, and it was found that roadway width and lateral pressure coefficient are the main factors affecting surrounding rock deformation. Numerical simulation revealed that as roadway width and lateral pressure coefficient increase, the plastic zone in the roof strata expands laterally and into deeper areas. Finally, the mechanical properties of different grout consolidation bodies were investigated, and the grouting effects under different grouting ranges were obtained. A bolt‑grouting collaborative support method was proposed. Field tests showed that the roof‑to‑floor convergence was reduced by more than 60%, indicating good support performance.
Kai Zhou, Chengfu Ma, Fenghai Yu et al.· Scientific Reports· 0 citations
