| As is acknowledged, raw coal is soft and difficult to take samples. Although it is easy to implement coal processing, big differences exist between briquette coal and raw coal sample in the hole and fissure structure, which therefore, fails to reflect the permeability properties of raw coal. This paper presents a mechanism of phenolic resin, and performs seepage tests under the condition of compression by using phenolic resin package lump coal, and finally figures out the empirical formula of Fluid-solid coupling. With the help of FLAC3D software, also the compile FISH language, a methodology is raised in this paper based on cusp catastrophe theory of waterproof coal pillar strength subtraction; in addition, combined with the Xin’an mine water inrush condition, through numerical simulation, this paper comes up with the minimum reasonable size of coal pillar, in the case of different goaf water pressure under the condition of the old kiln waterproof. Main tasks of this paper are as follows:(1) Ratio analysis and production of raw coal specimen in phenolic resin package. Aimed at the fact that raw coal is easily broken and hard to forming, and it is not conducive to the experimental study of stress and seepage coupling effects. Also due to phenolic resin stable room temperature mechanical properties and transparency high after solidification, this paper taking phenolic resin to package coal sample and do stress and seepage coupling experiments. The specimen can truly reflect the fracture structure of coal mining working face, and could provide a new carrier for the study of the same coal permeability experimental study, solving the technical problems of the difficulty of broken coal sampling and the limited sampling size. Meanwhile, the raw coal in phenolic resin package raw coal specimen is taken from large size and irregular raw coal to make sure the original structure of the coal basically is not affected.(2) Permeability test of the specimens of raw coal in phenolic resin nder the conditions of compression. Performing experiment to measure loading ways of the different stress, stress size and water pressure of coal samples under the condition of seepage flow by adopting parallel coal sample joint plane stress load and vertical loading ways of the joint plane loaded coal samples. Test results show that when the lateral pressure parallel raw coal joint direction, along with the increase of stress and seepage discharge increase, while when the vertical direction of raw coal joint stress, with the increase of stress and seepage discharge decrease. By numerical simulation analysis of the experimental data, the fluid-structure interaction equation under the condition of three dimensional stress can be obtained.(3) Analysis the stability of Henan xinan coal mine waterproof coal pillar. In view of the great energy co. LTD. Henan Xinan coal mine water inrush frequent accident, this paper analyzed the cause of mine water inrush based on detailed statistics of Xinan coal mine water inrush cases over the years. To study the minimum reasonable thickness of the waterproof coal pillar by doing the analysis of the waterproof coal pillar under the action of fluid-structure interaction, different strength reduction factor, the mechanical properties of waterproof coal pillar and waterproof performance. Catastrophe theory model is also very good to verify the waterproof coal pillar thickness and the function relationship between the reduction factor. In Xinan coal mine geological mechanics conditions of coal seam, coupling analysis found that with the increase of goaf water pressure, the minimum reasonable thickness of the waterproof coal pillar also continue to increase, When the water pressure is 1 MPa,2 MPa,3 MPa, 4 MPa,5 MPa respectively, the minimum reasonable thickness of the waterproof coal pillar is 15.4 m,17.19 m,20.67 m,23.94 m,27.96 m. |
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