| Soft rock drift supporting is an important and complex technical problem of domestic and overseas'underground engineering in nowadays. In recent years, drift occurred spalling and roof falling many times in the process of basic construction and mining in Ning Dong mining area, restricted the quick excavation seriously, directly affected the mine construction process and safety—efficiency mining.Based on large amounts of literature, concluded and summarized the concept and classification of soft rock, analyzed the factors and causes of soft rock drift surrounding deformation and failure, discussed the mechanism of restricting soft rock drift surrounding deformation and failure ,and the mechanism of combining support with the cable-net-anchor.Based on the site investigation of 1121 working face's drift in Hong liu Mine and the mine pressure observation lasted for a year, concluded the causes of 1121 working face's mining drift surrounding deformation, in the process of the mine pressure observation, used digital display convergence instrument, multiple base point roof separation indicator, loose circle tester, borehole camera and other advanced instruments to judge surrounding rocks'stability and security level.On this basis,Through the theoretical calculation method of Arch of natural equilibrium and the theory of surrounding rocks loose circle, and.using the bolt dynamical information design method ,Preliminarily Calculated the basic parameters of new roadway supporting design.Taken 1121 working face mining drift in Hong liu Mine for researching object, made roadway similar simulation in the 3d loaded physical simulation experiment table, the size of the model is 1500×1500×600mm, respectively using hydraulic jack loading system, imposed different lateral and vertical load to simulate the horizontal and vertical stress field of different buried depth drift. half of the drift was simulated by the initial supporting scheme, the other half was simulated by new scheme. Using optical electronic total station, pressure sensor, bolt dynamometer, dial indicator and other various test measures to observe surface displacement of the drift, deformation and failure of the deep surrounding rocks, supporting pressure distribution of the bottom, and force of the bolt tail part. Finally, combined with site measured results, verified the data of different test measures.Using FLAC3D numerical simulation method to analyze and compare the initial supporting design with the optimized supporting design scheme, obtained surrounding rocks'separation, displacement and stress distribution regularity of different positions and various stress environments.The study concluded that roof surrounding rocks loose circle ranged in 0~2.3m, the separation area mainly appeared in roof upper side 3~2m, the new supporting design schemes with 3m bolt can effectively limit the rock deformation and stress distribution. |
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