Abstract:
When coal mining enters the deep, the characteristics of high ground stress, complex geological structure and strong mining disturbance become more and more obvious. Aiming at the problem that the deformation of two sides is serious and difficult to control in the process of excavation due to stress disturbance in deep coal roadway, the stress evolution law of excavation roadway under small structure and mining disturbance is studied. Based on the point cloud data of the gas drainage borehole group in the underground floor rock roadway, the three-dimensional geological model of the working face was reconstructed, and the inclined coal seam, continuous fold and coal seam thinning zone in the roadway were identified. The three-dimensional model is imported into FLAC
3D to simulate the coal roadway excavation and working face mining. The results show that in the small geological structure area, the peak compressive stress of the tunneling head is larger, and its change rate with the tunneling distance is also higher. The maximum values of peak compressive stress at inclined coal seam, fold and thinning zone are 19.62, 19.25 and 19.86 MPa, respectively, and the maximum values of compressive stress change rate are 16.12%, 12.8% and 11.51%, respectively. The maximum compressive stress is not more than 19 MPa and the maximum change rate of compressive stress is not more than 10% when the coal seam with uniform thickness is excavated. When the mining distance is small, the excavation stress and the mining stress do not interfere with each other; as the mining distance increases, the displacement of the surrounding rock of the excavation roadway increases, and the mining stress continues to expand, gradually playing a dominant role, causing strong stress disturbance to the excavation roadway. After adopting the energy source control method of strong-weak coupling structure of hydraulic punching and grouting reinforcement in the field, the gas content and pressure of the coal seam are reduced, the strength of the surrounding rock of the roadway is enhanced, and the deformation of the two sides is reduced by 57%, which significantly reduces the probability and risk of coal-rock dynamic disasters. This study can provide basic theoretical support for effectively ensuring the safe mining of deep coal roadway.