Research on spatiotemporal evolution law of surrounding rock fractures and hierarchical collaborative control technology in high-stress soft rock roadway: A case study

Abstract

Safe and efficient coal mining has always been restrained in high-stress roadways due to their highly rheological property and large-scale deformation, which are key technical problems to be solved in this industry. In this work, the high-stress roadway of Wuju Coal Mine in Gansu, China is taken as the engineering background. First, long-term field tracking survey was conducted on the cracks of the surrounding rock during excavation to quantitatively analyze the spatial-temporal evolution law. Meanwhile, using the principle of simplicity, the variation trends of radial and axial permeability were revealed and the optimal grouting time in this roadway was determined. We proposed the theory of anchor grouting support with fixed anchor length, as well as hierarchical collaborative control technology (HCCT). The high-strength hollow grouting cables and corresponding anchor-grouting methods were also investigated and identified, which addresses the long-standing technical contradiction between grouting support and pressure deformation. Engineering test proves that this new technology can realize the safe and efficient control of high-stress rock roadway, with the maximum crack depth on the roof reduced from 7.65 m to 3.10 m and the surrounding rock deformation decreased by more than 56%. This paper provides new ideas for the maintenance and control of rock roadways or tunneling projects in similar conditions.