Key techniques for surrounding rock reconstruction and large deformation control under deep and multi-purpose roadway conditions

Multi-purpose roadway is an effective way to realize the joint control of gas in protective layer and protected layer,and to control the gas in a stable,fast and efficient way.However,the roadway is inevitably subjected to repeated mining in multiple working faces,and the surrounding rock deformation is extremely severe.In order to solve the problem of large deformation control of roadway surrounding rock under the synergy of high stress and multiple mining stress，taking No.17181(1) gas integrated management roadway as the engineering background in Pansan Mine of Huainan Mining Area.On the basis of geomechanical evaluation methods,such as geostress test analysis,mechanical properties of surrounding rocks,and drilling and peeping,a series of key techniques for rock reconstruction and large deformation control of roadway under multifunctional conditions were studied and applied.The hole wall grouting anchor cable was used to synchronously realize the grouting reconstruction of the surrounding rock of the roof after mining and the re-anchoring after the inner anchor of the anchor cable is destroyed.Based on the research and development of leaf stirring anchorage cable,the anchorage agents were fully mixed,and the strength and reliability of internal anchorage were significantly improved.The use of high-strength and high-rigidity box beams makes the load-bearing capacity of the anchor cable assembly more than 8 times higher than that of No.14 groove steel.The engineering application results show that the test roadway can withstand the influence of double mining of two adjacent working faces,and creates favorable conditions for gas extraction of the third working face nearby,the multifunctional roadway can be realized,and significant technical and economic benefits can be achieved.