Research on section optimization and deformation control technology of thick coal seam roadway with large inclination angle

In response to the difficulty of controlling the deformation of surrounding rock in coal seam roadways with large inclination angle, taking the main transportation roadway of Laoshidan Coal Mine as the research background, the distribution law of mine stress and the deformation and failure characteristics of roadways are analyzed. Numerical models of different roadway section shapes are established, and the distribution characteristics of surrounding rock stress, displacement, and plastic zone of roadways with different sections are analyzed. The optimal section of Laoshidan Coal Mine coal seam roadways with large inclination angle is obtained. The technical parameters of roadway anchor bolt and cable support are obtained by calculating the load on the roof and side of the roadway. A roadway support technology scheme is formulated and applied underground. The results show that the maximum horizontal principal stress in Laoshidan Coal Mine is at an angle of 46°-61° with the main transportation roadway. A large angle is not conducive to the stability of steeply inclined rock layers, resulting in shear slip failure characteristics of steeply inclined rock layers. Numerical simulations show that different sections of roadway exhibit varying degrees of stress concentration, with straight wall arch and three center arch sections being better than rectangular and trapezoidal sections. The stress distribution of the surrounding rock in the straight wall arch section roadway is relatively uniform, and the distribution range and displacement changes of the plastic zone are better than those in the three center arch roadway. The straight wall arch section is determined as the optimal section for coal seam roadway with large inclination angle in Laoshidan Coal Mine. Improving the stability of surrounding rock in steeply dipping rock layers is the key to controlling rock deformation. Based on this, a high prestressed anchor bolt support technology is proposed to suppress the sliding control of steeply dipping rock layers. The key technical parameters of anchor bolt and cable support are obtained through theoretical calculations and on-site measurements. The underground application effect shows that the anchor bolt and cable tends to stabilize after being subjected to force for 30 days during the monitoring period, with little change in the force of the anchor bolt and cable. The maximum deformation of the two sides is 33.4 mm, and the maximum deformation of the roof and floor is 45.1 mm. The displacement of the surrounding rock surface of the roadway is significantly reduced, and the deformation control effect of the coal seam roadway with large inclination angle is achieved.