Research On The Support-relief Coordinated Control Technology Of Surrounding Rock In The Face-to-face Excavation Roadway In Tanyaoping Coal Mine

In recent years,with the increase of mining intensity of coal mines,the situation of tense excavation replacement is common.Driving the roadway facing the mining face can effectively relieve the continuous tension of the working face.It is prone to serious deformation of surrounding rock,failure of supporting components,and difficulty in roadway maintenance.Based on the engineering background of Lvliang Tanyaoping Coal Mine’s opposite-to-excavation roadway,this paper comprehensively adopts the method of theoretical analysis,numerical simulation and field test to carry out research,carries out geomechanical test and drilling peep on the experimental roadway,and analyzes the opposite-to-excavation roadway.Based on the evolution characteristics of the overlying rock structure,the reasonable width of the coal pillars was studied,the roof cutting pressure relief effect of the drilling holes with different spacings was compared,and the support-pressure relief coordinated control technology for the surrounding rock of the mining roadway was proposed,and the following conclusions were obtained:(1)Through the investigation of the mine pressure manifestation of the roadway,it is found that the roadway facing the mining is prone to serious deformation of surrounding rock,failure of supporting components,and difficulty in maintaining the roadway.During the excavation process,it is affected by the strong mining of the adjacent working face,and the support parameters and schemes are unreasonable,so the surrounding rock deformation of the roadway under the mining conditions cannot be effectively controlled.(2)By establishing the lateral roof fracture model of the goaf,the theoretical analysis of the energy release of the roof structure and the instability failure conditions of the coal pillars are carried out.By changing the roof structure,reducing the coal pillar load,while improving the coal pillar support strength and increasing the coal pillar width can improve the coal pillar stability.(3)Through the numerical simulation of the plastic zone,stress and surrounding rock deformation before and after top cutting of coal pillars with different widths,it is found that the coal pillar width directly affects the stress environment of the surrounding rock of the roadway.The stress concentration factor gradually decreases,and the tunnel section shrinkage rate also decreases accordingly,especially when the coal pillar width increases from 17 m to25 m,the vertical stress distribution and deformation characteristics are improved most obviously,and the effect of continuing to increase the coal pillar size decreases;The roof can effectively relieve the stress concentration degree of the surrounding rock of the roadway:when the width of the coal pillar is 24 m,before the roof cutting,the coal pillar stress concentration coefficient and the roadway section shrinkage rate are 3.33 and 32.88%,respectively.After the roof cutting,the coal pillar stress concentration coefficient and section shrinkage rates were 2.14 and 5.44%,respectively;comprehensively comparing the stress and deformation laws of surrounding rock before and after top-cutting of coal pillars with different widths,the coal pillar width was finally determined to be 25 m.(4)Through theoretical analysis combined with numerical simulation,the feasibility study of dense drilling top cutting is carried out,and it is determined that the reasonable spacing of dense drilling is 400 mm when the diameter of the drilling is 65 mm;The evolution characteristics of vertical stress and elastic energy in the process of trough facing and mining are analyzed.The vertical stress and elastic energy change in the process of facing mining and mining go through three stages: the initial stage(50 m in front of the working face),the rapid rising stage(50 m in front of the working face to 150 m in the rear)and stable stage(150 m away from the rear of the working face),in which the 30 m range in front of and behind the working face is most severely affected by mining.(5)On the basis of leaving a 25 m coal pillar,the technical scheme of intensive drilling,roof cutting,pressure relief and subsection support collaborative control is given.The field industrial test shows that: from the excavation of the roadway to the end of the mining impact,the roadway The cumulative deformation of the roof and floor is 70-85 mm,and the cumulative deformation of the two sides is 110-130 mm,while the surrounding rock inside the roadway is less damaged after being affected by the mining face,indicating that the intensive drilling roof cutting pressure relief and the coordinated control of the sectional support The technology realizes the effective control of the mining on the surrounding rock of the excavation roadway.