Stability Analysis Of Surrounding Rock Of Soft Rock Roadway In Luling Coal Mine With Three Core Arch Large Section And High Ground Pressure

As the underground shallow coal resources drying up,the energy demand increases,the further development of coal mining in our country increasingly,the difficulty of support at the same time also will increase,the phenomenon of deep high stress leads to shallow unable to support the normal use of roadway surrounding rock supporting way,for this kind of phenomenon,paper in luling coal mine three centered arch large cross section as the research background,high pressure soft rock tunnel excavation Using the field survey,laboratory test,theoretical calculation and numerical simulation methods of analysis and field industrial test,studies the deep soft rock roadways with heavy section near the roadway section size,the horizontal and vertical direction and the stability of the roadway surrounding rock under different support forms,and puts forward the secondary support scheme of roadway to reinforce further,get a good control of roadway surrounding rock,The main research results are as follows:(1)By analyzing the deformation characteristics of the surrounding rock of the roadway with large section,the variation rules of surrounding rock stress,displacement and plastic zone under no support and support are deduced.On this basis,the influence formula between the roadway radius and surrounding rock displacement is obtained.Through FLAC3 D numerical simulation software,it is determined that under certain conditions,with the increase of arch span ratio,the deformation of the roof and floor surrounding rocks increases,and the displacement of the side surrounding rocks decreases.(2)Near the minimum spacing of roadway are analyzed and the stress range,through the numerical simulation of the horizontal and vertical direction near the roadway with different spacing to test the influence law of roadway,get roadway stress level near the overlapping phenomenon occurs mainly in the help of roadway section perpendicular to the roadway stress near the overlapping phenomenon occurs mainly in the roof and floor,when the horizontal and vertical spacing in 15 m or more,The deformation of roadway surrounding rock remains consistent as a whole.(3)The numerical simulation model of six different support schemes was established.By comparing the change law of stress field and displacement field,scheme 2 was finally selected as the best support scheme combined with economic benefits.The ultimate bearing capacity of secondary support structure was calculated by using the design principle of secondary support,and the creep deformation of roadway was effectively controlled.The control effect of roadway surrounding rock under the secondary support is analyzed by numerical simulation,and the final support scheme of the floor roadway is determined.(4)The field industrial test was carried out to observe the mine pressure of the test roadway.The results show that the supporting scheme of the primary bolt cable support and the secondary anchor net spraying + grouting support in the floor roadwayⅲ 1024 can effectively improve the large deformation of surrounding rock,and the surrounding rock deformation is well controlled.Figure 50,Table11,references 83...