The Law Of Gas Seepage And The Method To Determine The Stratum Of High Drilling Hole In Large Mining Height Working Face

The technology of high bore gas extraction is one of the effective ways to prevent and control gas disasters.In this paper,the jin coal group sihe coal mine gas in the large mining height sequence mining gas high precision drilling horizon identified as engineering background,analysis the influence of gas migration rule to mining of opening,large mining height are studied under the condition of different opening of the relationship between permeability and stress and strain of surrounding rock,put forward high order in sihe coal mine mining drilling horizon accurate determination method.The main research results of this paper are as follows:(1)The characteristics of the variation of mining stress in the high gas extraction area during mining with different sizes of adjacent cavitation areas were analyzed,and the triaxial seepage experiment scheme of coal and rock sample loading and unloading along the mining stress path under different immediate cavitation conditions was designed.The gas seepage characteristics of coal and mudstone samples with different damage under the stress path of total stress strain,axial pressure and axial pressure are analyzed and tested.The results show that the permeability of fractured coal and rock decreases gradually with the increase of stress,and the change range of permeability in the second loading and unloading is relatively small,and the loss of permeability also decreases gradually.(2)Set up different damage degree of coal sample loops and unloading stress and permeability model,and with the aid of laboratory triaxial seepage experiment,fitting for injury of different coal sample coupling model stress and permeability in the process of mining and analysis in the process of fracture at different time of coal or rock unloading stress sensitivity,and the damage of coal samples under different seepage and stress coupling model in COMSOL,combining cell damage variable seepage module for secondary development,multi field coupling model analysis different influence factors on gas drainage CaiLiang ratio,borehole surrounding gas pressure distribution and evolution law of permeability,The results show that fracture permeability and gas pressure borehole size have great influence on the cumulative gas production of pumping borehole,while matrix permeability has little influence on the cumulative gas production of pumping borehole.(3)Taking the East Wupan area of Sihe Mine as the geological prototype,the stress evolution and overburden permeability evolution characteristics of goaf overburden under different adjacent goaf sizes are simulated and analyzed.Fluent numerical simulation software was used to compare and analyze the gas drainage effect at different end hole levels of each working face of different air mining,and to determine the optimal layer layout of high hole drilling under different air mining conditions.The results show that the optimal layout of high position drilling in full solid coal mining is 35~40 m,the optimal layout of high position drilling in unilateral single air mining is 40~45 m,and the optimal layout of high position drilling in unilateral double air mining is 40~45 m.(4)Pure gas flow rate and gas concentration as evaluation index,analyzes the different mining under the condition of high pure gas flow in the process of drilling extraction and gas concentration with the drilling strata,the extraction of negative pressure change characteristics of gas emission in the process of mining face was studied,high drilling gas extraction rule and comprehensive governance effect,ultimately determine the high precision drilling extraction parameters in sihe coal mine,puts forward the high gas drilling horizon,and a method for determining the specific in east five panel of 5010 working face in sihe coal mine was measured.The paper has 114 figures,34 table,136 references.