With the increase in coal mining depth and ground stress, and the decrease in coal seam permeability, gas accidents occur frequently, which seriously threatens coal mine safety production. The current fundamental method of gas management is gas drainage, and one of the key links that determines the effect of gas drainage is drilling and sealing. This subject is based on the research background of the development and evolution of gas leakage passages in gas drainage boreholes and plugging materials, and adopts research methods such as mechanical analysis, numerical simulation, ratio experiment, performance test and field test to dynamically seal mucus in gas drainage boreholes. The materials have been studied in depth, and the details are as follows:
(1) The uniaxial compression-acoustic emission experiment of the raw coal sample was carried out, the acoustic emission information of the coal sample was collected during the compression process, the damage evolution model of the compression failure process of the raw coal sample was established, and the failure characteristics of the coal sample under compression were analyzed; Using the self-made hole-sealing grouting three-dimensional simulation test platform to simulate the evolution of the air leakage channel under pressure during the drilling process and after the drilling is completed, and obtain the leakage of the hole-bearing coal sample The development and evolution of air channels.
(2) Considering the shape of the gas leakage channel around the gas drainage borehole, with the help of COMSOL Multiphysics simulation software, the seepage distance of the sealing slurry with different viscosity under different grouting pressures is simulated, and the appropriate viscosity range of the slurry is determined.
(3) The composition of the new type of sealing slime material was screened, and the feasibility of the material was analyzed; single factor experiments were carried out to explore the influence of the content of each component on the performance of the slime material; through the design of multiple sets of orthogonal experiments with different dosages , So as to select a set of optimal mix ratios, and conduct laboratory tests on its expansion, water retention and sealing performance.
(4) On the basis of theoretical research and experimental research, the return airflow trough of 2802 working face of Zhangcun Coal Mine of Lu'an Group is selected as the test site, and the test hole and the contrast hole are sealed with new and traditional viscous materials, respectively, and gas drainage is observed. Concentration and mixing amount of gas drainage to verify the superiority of the new slime material.
The research results revealed the development and evolution of gas leakage channels in gas drainage boreholes, and developed the sealing mucus materials needed in the "strong-weak-strong" dynamic sealing method, and studied its performance, which improved the dynamic sealing method to a certain extent. The sealing effect is of great significance to the drilling and sealing field operations, and helps to improve the efficiency of mine gas drainage.
谷歌
火狐
