Seepage Argillaceous Roadway Instability Mechanism And Safety Control Measures

Because of the highly stress, loosed and politic surrounding rock and easily water affected etc., complicated geological conditions, roadway in Huaibei mining area is water seepaged and politic. This article aims at a further study of surrounding rock stability control problem. By intensive engineering geology survey, lab test, molecular simulation and numerical calculation, this article analysis the reason the confined water seepages in the unstable roadway, reveales the evolution rule, get the mechanism of the water seepaged and politic roadway loosing the stability and develop the control measures. The research achievements are as listed below:(1) Intensive site surveys find that the roadway surrounding rock become flowing deformation and argillization under the combined action among argillaceous soft rock, confined water and stress disturbance. This makes the roadway water seepaged and unstable. Essentially, the instability and deformation is result of combined action of ock seepage field, stress field and damage field. However, the vadose water erosion is the key factor for deformation of the roadway(2) By scanning electron microscopy, the analysis on typical mudstone micro structure and material composition through X- ray diffraction and double cell structure model of smectite established with the help of Materials Studio(MS) software, this article shows a hydration process in which the smectite adopts water molecules and becomes 1, 2, 3 layers of water saturated molecular layer. As the the hydration of clay and mineral serious, more and more micro particles fall off and fractures appear. This macroscopically result to the flowing deformation and argillization of the rock.(3) The test uses the Forcite set in MS software to make the molecular ernergy optimization model of smectite to find irregular variation in the polyhedron structure of smectite molecular model. At the same time, the model’s total energy is greatly reduced and forms the minimization of energy structure, resulting the mud rock’s loss of mechanical strength. This is the direct cause of the break in mud rock’s micro structure. Finally, it becomes the no strength- argillization mixture.(4) The test studies the change rule of displacement in permeable mud roadway by numerical simulation. We found that the roadway deform rapidly after excavation; the roof baseplate and the two sidewalls move between reaches 1500mm; the roadway’s net sectional area reduced 50%. The argillizated surrounding rock cannot keep the roadway’s stability at all. ·(5) Aiming at the instability mechanism of the permeable mud roadway, this paper formulates a set of safety control countermeasure by dewatering, depressurization intensifying the surrounding rock and strengthening supporting. Its essence is based on the guidance of confined water to replace the original mud rock for concrete wall.With grouting method and continuously improving the overall’s strength and stability of mudstone, it build tough a much whitewashing-seal structure and highly paste the rock, which becomes a roadway support circle system.(6) The Level II horizontal belt roadway in Huaibei Area Zhuxianzhuang Coal Mine carried out validation research and industrial test about the governance of water seepaged and politic roadway. The effective result indicates the governance method is proper. This ensures the normal uses of the roadway and gets perfect economic and social benefits.The paper has 50 figures, 6 tables and 90 reference together...