Study On The Mechanism And Control Technology Of Floor Heave Of Gob-side Entry In Deep Large Section Of Shilawusu Mine

In this paper,the research carrier is the track channeling of 221 upper 01 working face in Shilawusu Mine.Combined with the field investigation,through the theoretical analysis and laboratory test,the mechanism of floor heave in the deep large section gob side driving roadway is obtained.Combined with the design principle and theoretical calculation of the reasonable width of narrow coal pillar,the reasonable width is determined by numerical simulation.Based on the principle of high-strength prestressed bolt and cable support and the principle of borehole pressure relief.This paper puts forward the dynamic control technology of the pressure relief of the bottom drum support of the deep large section gob side driving roadway.It is verified by industrial test.(1)Large buried depth and large section of roadway along goaf in working face 221 upper 01 of Shilawusu Mine.In the face of large in-situ stress and complex stress conditions etc.There are many clay minerals in the rock of the floor,and the floor is easy to expand when encountering water.The roadway driving along the goaf is affected by multiple complex conditions such as multiple mining and weakening of coal body water leaching.The tunnel production condition is a complex multi disaster coupling production condition.It is very difficult to control the surrounding rock of roadway under this production condition.It is easy to produce bottom drum.(2)Based on the analysis of the movement law of the overlying strata in the gob side entry with large section and narrow coal pillar,the change law of the stress and strain of the surrounding rock of the entry is obtained.According to the stress-strain distribution of the floor rock the mechanical model of the floor is established.The analysis shows that the main factors of roadway floor heave are complex surrounding rock stress field,the nature of the surrounding rock of the floor,the role of water management and the supporting scheme.It is determined that the roadway should be a compound floor heave of flexure fold type,extrusion flow type and water swelling type.(3)Based on the geological conditions of the track along the groove of the working face 221 upper 01,the FLAC3 D three-dimensional calculation model is constructed.This paper studies the control effect of different narrow pillar width and different support parameters on the floor heave and the control analysis of the pressure relief of the side drilling on the floor heave.Determine a reasonable narrow coal pillar width of 5m.Determine the bolt(cable)material,diameter,spacing between rows and preload and other parameters.Pressure relief hole depth is 20 m.The distance between pressure relief holes is 1m.(4)The dynamic control technology of "high strength anchor cable + steel belt + metal mesh + shotcrete + pressure relief hole" is put forward.By means of surface displacement monitoring,bolt support resistance monitoring,surrounding rock fracture development monitoring and stress distribution monitoring in coal body,the tunnel is observed.The results show that the maintenance status of the test roadway section is complete.It is verified that the technology can effectively control the floor heave of roadway.The paper has 70 figures,9 tables and 83 references.