多煤层重复采动回采巷道失稳机理与控制技术OA北大核心CSTPCD

The working face of W9-10-22290 is an isolated working face in the second mining area of the third level of Pingmei No.6 coal mine.The outer section of the air roadway will be affected by the mining of the overlying W8 and the underlying No.5 coal mine during the mining service,and the mining space-time relationship is extremely complex.Objectives To explore the instability mechanism and control technology of repeated mining roadways in multiple coal seams,Methods based on the spatio-temporal evolution relation-ship of stress in the mining face,a surrounding rock control method for the entire lifecycle of the outer sec-tion of the air roadway in the W9-10-22290 working face the Pingmei No.6 coal mine was proposed and ap-plied in field engineering.Results The results showed that the roof of the roadway presented tensile shear failure after the close coal seam mining.During the mining process of the coal seam and the underlying coal seam,the roadway would be subjected to advance abutment pressure step by step.According to the spatio-temporel disturabnce and high-stress environment of the surrounding rock of the roadway,a comprehensive surrounding rock control technology of combining resistance,yielding,and pressure relief was proposed,which included"high pre-stressed high-strength bolts+anchor cables+deep hole blasting for pressure relief".Field industrial tests showed that the maximum deformation of the two sides during tunnel service was 347 mm,and the top settlement and floor heave were within the controllable range,which could meet the require-ments of mine safety production and achieve better technical and economic benefits.Conclusions The re-search results provided a reference for the surrounding rock control of mining tunnels under similar condi-tions.