| Rock drift in floor is a familiar kind of high stress roadway that is affected by coal seam extraction. The maintenance and rebuilding problems will much more outstanding while the roadway is under the condition of dynamic pressure and softrock or deep mine. These problems cause great deformation and great ground pressure. The roadway is very difficult to support and the supporting cost is heightened in a great extent. The normal activity of the mine and the balance of preparation and winning work are also seriously affected. Therefore, how to solve the supporting problems of this kind of roadway is one of the most complicated technological engineering roadblocks in the field of underground engineering around the world nowadays, it is also a key problem for underground resources extraction.The maintenance status of the main development and preparation roadway of Renlou mine in Wanbei mining area were good without mining influence, but the deformation and damage of the roadway were very severely when the roadway was disturbed by coal seam extraction. The fore effect distance and effect extent were so great, which badly affected the roadway. About half length of the roadway needed several times of overhaul and it was very difficult to maintain the roadway. So the normal production sequence of the mine was seriously affected.The paper summarized the failure characteristics of rock drift affected by dynamical pressure in Wanbei mining area through the evaluation of the surrounding rock status, the field investigation of the deformation and damage status, the analysis investigation of the reasons of the roadway's deformation and damage. Based on the latest research achievement, the concept of mining sensitivity roadway was first put forward in this paper.The analysis investigation on the mechanics status of the surrounding rocks, deformation characteristics, and mechanics mechanism of the deformation of the mining sensitivity roadway was done in the paper by the methods of field investigation, physical mechanics properties test of the surrounding rocks, numerical simulation and equivalent material simulation. Then the concept of supporting weak structure was put forward. The positions where possibly are the supporting weak structures were analyzed by using the theory of elasticity combined with the boundary element and finite element methods in an isotropic surrounding rock condition. The theoretical arithmetic results primarily accord with the results of the field investigation and numerical simulation.The existence of the supporting weak structures make the deformation and damage of the roadway surrounding rocks present heterogeneous and complicated phenomena. For the roadway surrounding rocks, the supporting weak structures are generally the key positions to initiate the damage of the roadway. Based on the features and control mechanism of the weak structure of the supporting, the technology system of non-uniformity control by reinforcement supporting on the supporting weak structures was put forward. The non-uniformity control system mainly includes controlled blasting technology, high performance bolt supporting technology, little bore diameter and short prestress anchor cable supporting system, and surrounding rock grouting reinforcement technology.On the basis of the research achievements of the paper, combined with the maintenance characteristics of Zhongsan track crosscut in Renlou coal mine, the technology schemes of non-uniformity control for key parts were made. The deformation and damage of the roadway surrounding rocks caused by over-the-roadway extraction were effectively controlled, the difficult problems of the development roadway and preparation roadway control in Renlou coal mine were successfully solved the, the normal balance of preparation and winning work was ensured, powerful guarantee for safe and high efficiency production and continuable development of the coal mine were provided, and good economic and social benefits were also obtained. |
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