Study On Roadway Layout And Support Technology Of Fully Mechanized Mining Under Extra Thick Soft Coal Seam

According to the thickness and the geological environment of the surrounding rock,the method of full high stratification and caving coal mining or the combination of the three techniques can be selected.In the layered mining,it is difficult to support the staggered roadway because it bears the upper layered support pressure,So it's rarely used in actual engineering.However,it has great advantages in exploiting the superior efficiency of fully mechanized coal mining equipment and improving the coal recovery rate.Taking wangwa Coal Mine 110502(2)stratified working face wind tunnel as the main research object,the driving direction and external dislocation distance of stratified wind tunnel are adjusted in time by means of survey and comparison,theoretical calculation,mechanical property test of surrounding rock,numerical simulation and field monitoring,and the supporting parameters are optimized.In this paper,the application of the roadway layout in the thick and soft coal seam is successfully carried out,and the effective support technology is put forward.By comparing multiple borehole column diagrams and field investigations,The characteristics and thickness of surrounding rock of the roof and floor of the working face are found out.The coal and surrounding rock at different heights of No.5 coal seam were sampled,and the mechanical properties parameters of surrounding rock of roadway were obtained through relevant physical performance tests.Due to the elastic modulus E<15GPa and internal disintegration index Id,2?85%,the surrounding rock is considered as soft rock;No.5 coal seam is divided into upper,middle and lower layers with compressive strength of 13.06mpa,12.66mpa and 14.42mpa respectively.According to the distribution of coal and rock strata and physical and mechanical strength parameters of the working face around coal and rock,the mining model of the working face with lower layers is established,and the minimum size of the upper coal pillar is calculated by theoretical analysis and calculation as 16.62m..Uder the condition that both sides of the coal seam are closed,the width of the plastic and crushing zone of the lower layered coal pillar is 5.5m.The simulation of the lower layered wind tunnel is arranged in the outside of the 110502(1)goaf,and five different roadways are simulated.Study the changes of stress and displacement caused by tunneling at distances of 5.4m,10.4m,15.4m,20.4m and 25.4mCombined with the production conditions of mining roadway on site,the spacing between bolts and cables is shortened by theoretical calculation and numerical simulation,the pretightening torque is increased to 300N·m,and the deformation of roadway is reduced.The high-cost support method of shelving support for a long time in this roadway was gradually eliminated,which improved the tunneling efficiency and reduced the support cost.The secondary preloading of anchor rod(cable)is proposed to further ensure the stability of roadway.Figure 40 Table 10 Reference 68...