Study On Stability Analysis And Control Technplogy Of Surrounding Rock In Deep-seated Soft Rock Roadway

With the increasing depth of coal mining in China, the stress and tectonic stress of the original rock are increasing continuously. In the shallow part, the engineering rock mass, which is characterized by deformation and failure of hard rock, is transformed into high stress soft rock after entering deep, presenting violent ground pressure, high stress,large deformation, wide loose range and so on, which brings great difficulties and challenges to the support of the surrounding rock in deep soft rock roadway. Therefore, it is of great practical significance to study the deformation and failure characteristics, failure mechanism and stability control technology of deep soft rock roadway in deep soft rock roadway. Based on Longgu mine shaftbottom with 810 levels, this paper studies the stability control technology of surrounding rock in deep soft rock roadway by means of physical engineering, field measurement,theoretical analysis, numerical simulation, mine pressure monitoring,and other technical methods, and then makes the following achievements:(1) The paper analyzes the mineral composition of the surrounding rock, the basic mechanics parameters of the rock, the stress distribution of the roadway and the range of the loosening circle by means of laboratory test and field measurement technology, and summarizes the deformation law, deformation and failure characteristics and deformation and failure mechanism of the deep soft rock roadway.(2) The deformation behavior of roadway surrounding rock under different conditions and the reinforcement structure formed after grouting in roadway are analyzed. Based on the elasto-plastic theory, it is calculated that the ultimate bearing capacity of roadway surrounding rock is much larger than that of general support.(3) The numerical simulation software FLAC3D was used to simulate the roadway grouting. Respectively, to change a parameter of the elastic modulus, internal friction angle, cohesion, Poisson ratio, the other parameters remain unchanged. It is concluded that the convergence deformation of the surrounding rock is gradually reduced with the increase of elastic modulus, internal friction angle and cohesion; with the increase of the Poisson's ratio, the variation of the convergence of the roadway is smaller. Only change the slurry diffusion radius, the other parameters of the reinforcement ring after grouting remain unchanged.When the radius of slurry diffusion exceeds the radius of loosening circle,with the increase of the radius of slurry diffusion, the increase of the control effect of grouting on roadway surrounding rock is limited.Therefore, in order to obtain better economic results, the slurry diffusion radius should be greater than or equal to the radius of the loose circle of the roadway.(4) Aiming at the deformation and failure characteristics and engineering geological condition of deep soft rock roadway in Longgu coal mine, three - anchor combined support and anchor - supporting scheme are proposed. FLAC3D is used to simulate the support effect and verify the feasibility of the support program. The mine pressure monitoring scheme is developed to monitor the convergence of the roadway surface, the anchor and anchor force, and the separation of the roof of the roadway to improve and optimize the support scheme and verify the feasibility of the support scheme. This paper provides a feasible scheme for the support of deep soft rock roadway.