Analysis of the cusp catastrophe of stability of the false top of paste filling body
In order to address the problem of safe mining of the"three underground"(meaning the min-ing areas are arranged under buildings,railways and water bodies)thick coal seam overlying resources in the third Mine of Yaojie,we adopt the mining method of downward stratified paste filling.First,by constructing a mechanical calculation model for the false roof of paste filling,we could obtain the rela-tionship between its thickness and ultimate strength.Then,the total potential energy of the false top of filling body was derived by using the potential function of the cusp catastrophe theory,and its stability was explored.In the end,by using FLAC3D numerical calculation software,the numerical calculation model for the downlink layer paste filling mining is established,and the deformation characteristics of false top of filling body were studied.The results show that the ultimate strength of the false roof of the backfill is negatively correlated with its thickness as a power function.When the thickness of the false roof of the filling body is 3.2 m,its ultimate strength is 4.9 MPa.and when the thickness of the false roof of the filling body is greater than 3.2 m,its ultimate strength gradually stays at 2.9 MPa.The total potential energy of the false roof of the filling body satisfies the instability criterion △ ≥0,and the sud-den instability failure will not occur.The maximum principal stress of the false roof of the filling body and the lower layered filling body are both 1-2 MPa,which is less than its compressive strength of ulti-mate bearing.And the plastic zone appears in the lower layered filling body,and the shear or tensile fail-ure of the false top of the backfill does not occur.The tensile stress is stable at 0.65 MPa,which is far less than the allowable tensile stress of the filling body.The field measurements show that,the sinking of the false roof of the filling body and the cumulative compression of the upper and lower layered filling bodies is only 75 mm during the excavation of the lower layered filling.Therefore,on the basis of the layered filling false roof in the upper strata,the lower strata are mined,and false top of filling body can bear the overburden load that the upper surrounding rock exerts,ensuring its own stability and preventing fracture instability,and keeping the safe mining of the"three underground"thick coal seam overlying resources in the third Mine of Yaojie.
thick coal seam miningpaste fillinglayer miningnumerical simulationfalse top of fill-ing body
万方数据
维普
