Deformation mechanism and sidewall-roof collaborative control technology of high-stress soft rock roadway

To address the difficulty of controlling surrounding rock deformation of high-stress soft rock roadways under mining influence, taking the high-stress soft rock roadway of Yadian Coal Mine as the research background, this paper analyzes the deformation and failure characteristics of roadway surrounding rock and the evolution law of mining-induced stress. The in-situ stress of roadway surrounding rock as well as the mineral composition and content of surrounding rock were tested, and the influencing factors and mechanism of roadway surrounding rock deformation were revealed. The results show that the high-stress soft rock dynamically pressurized roadway in Yadian Coal Mine presents prominent failure characteristics of large deformation and full-section shrinkage. High in-situ stress and strong mining-induced effect are the main driving forces causing large deformation and failure of the roadway. Under the influence of high in-situ stress and strong mining-induced stress, the inward squeezing deformation of roadway side is the most prominent, which leads to continuous weakening of the integrity and strength of roadway side coal mass from shallow to deep, makes rock bolts basically fail, and the large deformation of roadway side aggravates the floor heave of soft rock in floor, thereby inducing full-section shrinkage deformation of the roadway. It is revealed that the deformation mechanism of high-stress soft rock dynamically pressurized roadway in Yadian Coal Mine lies in the imbalance of roadway side and roof support; the large deformation and failure of roadway side aggravate the overall deformation of roof and floor. On this basis, a high pre-stress support technology of strengthening roadway side and protecting roof is proposed. The supplementary support of roof rock bolts (cables) is adopted to restrain bed separation and deformation of roof strata. Grouting reinforcement of roadway side is used to improve the integrity and bearing capacity of fractured coal mass, and combined with high pre-stress rock bolts (cables) support to enhance the support strength of roadway side and surrounding rock stability. The underground application results show that under mining influence, almost no subsidence deformation occurs in the roof, the inward squeezing deformation of roadway side is reduced by 66.7%, and the floor deformation is significantly decreased, achieving a good control effect on the deformation of high-stress soft rock roadways.