Study on Coupling Support Technique in the Roadway of Hecaogou No. 2 Coal Mine with Soft Roadway of Large Deformation

Through the study of failure mechanisms in soft roadways accompanying by large deformation, their failures are mainly induced by the uncoupling between mechanism of support and rock as well as their strength and rigidity. The deformation starts from key parts and later leads to unstability of the entire support system. Therefore, coupling surrounding rocks and corresponding support is indispensable in terms of the stability in soft roadways. It can be found from a great deal of research and engineering practice that coupling in rigidity between bolts and surrounding rock is able to reinforce rocks to the greatest extent. Coupling in strength, however, is more likely to make its stress field and displacement field evenly distribute. Also, when it comes to coupling in structure, the strength of the surrounding rock can be fully utilized to support roadways. On the basis of engineering surveys and corresponding rock mineral analysis in Hecaogou no. 2 coal mine, it can be found that the major factors causing great deformation in soft roadways are high degree of weathering, quality of surrounding rocks, water penetration and improper support scheme. The surrounding rock is categorized as jointed expandable composite soft rock. And later its deformation mechanism is determined as I AC II BC III CEA, which promotes the new design of net-anchor coupling support for roadway repair.