Grouting reinforcement mechanism and practice of broken surrounding rock in deep buried roadway under dynamic pressure

Abstract

To address the severe engineering challenges associated with the intense fragmentation and structural deformation of surrounding rock in deep-shaft roadways subjected to dynamic mining-induced stresses, this study proposes a control methodology for stabilizing highly fractured rock masses in deep main roadways under dynamic pressures. By comprehensively integrating X-ray CT scanning with COMSOL and UDEC numerical simulations, we elucidate a grouting reinforcement mechanism characterized by a ‘strength enhancement—synergistic bearing—environment improvement’ paradigm. The optimal operational parameters for the grouting scheme were determined to be: an injection pressure of 2.0 MPa, a water-cement ratio of 0.5, a borehole row spacing of 2.5 m, and a borehole depth of 2.0 m. Numerical modeling indicates that, compared to the un-grouted condition, the fracture propagation depths at the roadway crown and floor were mitigated by 19.15% and 29.55%, respectively. Furthermore, the peak vertical stress within the surrounding rock was reduced by 20.64%, while the absolute convergence displacements of the roof-to-floor and rib-to-rib were significantly curtailed by 65.41% and 76.37%, respectively. The findings demonstrate that by augmenting inherent rock mass strength, cultivating a synergistic load-bearing architecture, and optimizing the localized stress environment, the proposed grouting technology achieves a multidimensional, volumetric reinforcement of the fractured rock mass integrating ‘lithology-structure-stress’. Following the in-situ application of the grouting technology, the empirical roof subsidence, floor heave, and rib convergence were significantly reduced by 80.59%, 83.13%, and 87.64%, respectively, compared to the un-grouted conditions.