Research On Mechanism And Control Of Deformation And Instability Of The â…¡66Dip Groups Of LiuQiao No.1Coal Mine

Systematically studied on stress distribution of Ⅱ level six mining area of Liuqiao coal mine and its influence on the roadway layout and analyzed surrounding rock deformation failure mechanism of Ⅱ66mining area down roadway by using field geological survey and test, laboratory rock mechanics test, theoretical analysis and numerical simulation, and put forward the corresponding control theory and the specific technical measures.Firstly, the deformation characteristics of down roadway were got from the field geological investigation, and has carried on the preliminary analysis. The physical and mechanical parameters of surrounding rock of roadway group and the law of stress distribution were obtained from the laboratory test and field test. According to the experimental results, using the method of combining theoretical analysis and numerical simulation, the roadway layout angle of Ⅱ level six mining area was N269°E or N197°E. The theoretical analysis shows that the approximate analytical solution of the surrounding rock stress field and displacement field during the period of heading down in track roadway group, and obtained the minimum deformation242mm without considering the creep deformation under the premise.The large numerical model of Ⅱ66mining area down roadway that can simulate the4coal and6coal mining was established by FLAC3D. The stress field and displacement field evolution of roadway surrounding rock were analyzed during the excavation of tunnel group down in the original design of the support. The results show that:the two stress field of roadway excavation superimposed on each other in the tunnel and the stress concentration degree increased significantly in the process of opening up the mountain, and asymmetric of roadway space layer resulting in the deformation of roadway is asymmetric. The stress field and displacement field evolution of roadway surrounding rock were analyzed under the influence of4coal and6coal mining, found out the weak parts of the existing supporting structure and determined reasonable compensation position of support surrounding rock bearing structure in the roadway open up on the basis of complete.The optimizational supporting schemes for each of dips among the dip group are proposed applying the theoretical analysis and engineering analogy. For rock drifts, a multilevel combination scheme consisting of U-shaped steel, yielding anchors(cables) with high strength and high initial stress and grouting method of fractional steps is applied, which is particularly focus on the use of the pretightening cables in the shoulder and foot for structure reinforcement to adapt to the asymmetric deformation of roadway. The engineering practice shows that the deformation of the surrounding rock is controlled in the reasonable range after the new support scheme is adopted and that the problem of the instability of the Liuqiao mine Ⅱ66dip group can be solved to guarantee the coal mine safety and high efficiency production.