Deformation failure mechanism of deep high-stress fractured soft rock roadways and active-passive full-space...

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.