Research On Group Anchor Support Mechnism Of Large Section Soft Rock Roadway Of Deep Shaft In Huainan Mining Area

The central and eastern regions of China are economically developed regions with large energy demand.With the development of shallow coal resources,the Huainan mining area mainly plans and mines coal resources of 800m deep.The coalbed deposit environment is dominated by the Carboniferous Permian system,which is a marine-continental interfacial clastic sedimentary stratum,and the crustal movement is relatively active.There are many folds and faults,which results in a large amount of large-section soft rock roadway engineering.Based on the analysis of engineering geological characteristics and the mechanism of group anchor support in deep roadway in Huainan mining area,the optimization design method of support parameters is proposed.The diversion room of the second level pump house of Zhangji Mine is used as the engineering background,and the numerical calculation and field measurement method are applied to the soft rock.The roadway group anchor support was analyzed and the following conclusions were drawn:(1)The distribution of rock strata in the deep well roadway of Huainan mining area is uneven,and the lithology changes greatly during the actual excavation process,which is complicated.According to the engineering analogy method,the support of different roadways is designed.The difference of parameters is small.The deformation characteristics of the roadway are characterized by large deformation,large initial deformation rate,obvious spatial effect,severe deformation of the bottom plate and stress sensitivity.(2)Group anchors have wall confinement effect on surrounding rock mass,anchor bearing ring effect,layered bearing effect of anchor(cable),and wedge-solid effect of loosely fractured rock mass.After the soft rock roadway group anchor support,there are usually stratification features of the fracture expansion stability zone,the strain softening zone,the plastic zone and the elastic zone.The stability of the surrounding rock should be strengthened by reinforcing the shallow rupture zone and strain softening zone of the roadway wall.It becomes the bearing structure and controls the principle that the plastic zone extends to the deep surrounding rock.(3)The support design of deep soft rock roadway should be gradually optimized from the aspects of geomechanics,roadway space location,surrounding rock and support coupling.For high-stress soft rock,soft rock with expansion components and extremely soft rock,different support strategies should be used for classification to design specific parameters.(4)It can be seen from the numerical calculation that the anchorage between the anchors is 0.6m-1.0m,which is beneficial to the stability of the surrounding rock.It can be seen from the field measurement that by encrypting the anchor rod and anchor cable spacing,the bearing capacity of the bearing ring structure is strengthened,and a better supporting effect is obtained.The deformation rate of the surrounding rock of the roadway is less than 1 mm/d,which ensures the pump room surrounding of the pump house.The rock is stable.Figure [37] table [4] reference [68]...