Study On The Seepage Characteristics Of The Surrounding Rock Of The Roof Of No.3 Coal Seam In Lu’an Mine Area

In this paper,the hydrogeological data in the study area are collected and collated,so as to analyze the current research status of the seepage characteristics of the surrounding rock of the roof plate of the No.3 coal seam at home and abroad.Taking the Daping Mining Area as the research object,the HB-2 briquette-like pore seepage adsorption simulation measurement device was used to conduct relevant indoor similar simulation experiments,and the response mode of permeability to the effective force and the dynamic change of permeability were characterized by defining the sensitivity coefficient of permeability to the effective force and the maximum damage rate of the permeability rate.After that,the computer is applied to conduct numerical simulation research,and the simulation results are analyzed and the corresponding conclusions are drawn.The main research results of this time are:(1)The permeability of the roof of the No.3 coal seam in the study area has a strong sensitivity to the effective force,the permeability of different surrounding rock combination methods decreases with the increase of the effect force,and there is a strong negative exponential correlation between the permeability and the effective force;the stress sensitivity coefficient of different surrounding rock combinations under unloading stress conditions is higher than that of loading;the permeability of different combinations of surrounding rocks under the same experimental conditions varies differently and the differentiation phenomenon is significant;the permeability is controlled by lithology,pore fracture degree and different surrounding rock combination methods.Among them,the combination of different surrounding rocks is the main controlling factor of the dynamic change of permeability.(2)Through the theory of multiple linear regression model,the relationship between the permeability of a single surrounding rock mudstone,sandstone and siltstone and the combined permeability of different lithology is studied,and the relationship between the constant and the influence coefficient intercept(b0),mudstone(b1),sandstone(b2)and siltstone(b3)is analyzed,and it is concluded that the intercept(constant b0)inhibits the permeability;the combination OF LA-2 and the combination of LA-4 is the most beneficial to promote the increase of the permeability,and the combination of LA-6inhibits the increase of the permeability.(3)Through the verification of the accuracy of the model of coal seam characteristics,gas content and gas content in Changcun Mining Area of Wuyang Mining Area,it was found that the simulation of the model was consistent with the actual existing strata,and the permeability of Tunliu Mining Area was predicted,and the permeability of Tunliu Mining Area was 0.0146 m D,which was low permeability.Therefore,the model can be well applied to the actual formation in combination with practical factors,and provide guidance before coal-bed methane is mined.