Study On Gas Seepage And Emission Law Of Coal Seam In Layered Filling Mining

With the continuous development of the coal industry,coal mining under buildings,railways and water bodies has seriously affected this industry.However,layered filling mining is an important means to solve this problem of thick coal seam.Due to the special method of layered filling mining,and the mining process involves the heat release of filling materials and the pore structure of filling body,the law of gas seepage and emission in coal seam and filling area is particularly complex.Taking E1302 working face of 3# seam as the working condition background,this paper explores the seepage and emission law of coal seam gas in the process of mining with layered filling method.Through the combination of theoretical analysis,laboratory test and numerical simulation,the solidification and temperature rise law of filling materials in the process of mine layered filling mining is studied.A mathematical model of thermal fluid solid multi field coupling considering temperature effect,seepage effect and skeleton deformation stress is established.Combined with numerical simulation,the law of coal seam gas seepage and emission under layered filling mining mode is studied.The main research results are as follows:(1)The self-designed temperature measurement system is used to test the heating law of filling material during solidification,and each stage of filling material heating is divided according to the change rate of temperature.Based on the hydration exothermic model of cementitious material,the test data are fitted,and the general law of solidification temperature rise of paste filling material is obtained.On this basis,combined with numerical simulation software,the change law of coal seam temperature under the influence of filling material heating is calculated.(2)The permeability and porosity of filling body and coal body are tested through experiments.By comparing the porosity and permeability of filling body and coal body,the pore structure characteristics of filling body and whether there is gas migration channel in it are clarified.(3)On the premise of considering the influence of coal seam temperature change,gas pressure change and the influence of coal pore structure characteristics on coal seam gas seepage,the coal deformation control equation,gas migration control equation and temperature field control equation are established.(4)Based on the actual working conditions,the geometric model is established,and the migration path,seepage velocity,pressure distribution law and emission mode of coal seam gas under the influence of layered filling mining are analyzed.(5)A method is proposed to calculate the amount of coal seam gas emission under the condition of layered filling mining by integrating the gas emission velocity on the coal seam surface.According to the comparison and verification of the field measured data of E1302 filling face in Gaohe energy 3# seam,it is proved that this method has high accuracy in predicting gas emission,which can provide a reference for the prediction of mine gas emission.This paper has 41 pictures,15 tables and 78 references.