Analysis Of Coal Mining Goaf Culvert Structure Performance And Safety Evaluation

Coal energy in our country has a pivotal position in the process of economicconstruction，meanwhile，mining of coal produced a large number of coal mining goafin the coal mining area. The culvert is the important hydraulic structure of thermalpower plant ash，It’s often through the coal mined-out area. The subsidence basin in thesurface caused by the coal mining would have a very adverse impact on the mechanicalstructure of the tunnel，and belongs to the underground structures，its is difficult tomake a repair after damage. So it is important to study the mechanical properties andmake an safety assessment of the culvert in the above goaf.The article adopts two methods of theoretical calculation and finite elementnumerical analysis method for the mechanical performance analysis and safetyassessment of the culvert in the coal mining goaf，this article mainly includes thefollowing aspects of content:(1) Elaborate theory of landfill soil pressure and the internal structure force ofculverts，and on the basis of this theory，using two methods of manual calculationrecommended by the different industry on the vertical soil pressure and calculate theinternal forces of structure of the culvert’ control section，obtained the vertical soilpressure and the internal force variation law of the culvert under the condition ofdifferent installation.(2) Finite element analysis software ABAQUS is adopted to establish thetwo-dimensional plane model and calculate the transverse internal force of the culvert，the reasonable contaction is adopted to simulate the interaction between soil mass andculvert，and using layered filling way of loading in order to accurately simulate the actual stress state of structure. Analysis the change rule of the vertical soil pressureunder the influence of the slope angle in the larger width groove. At the same time, thefinite element calculation results and the theoretical calculation results are comparedanalyzed.(3) Three dimensional model is established by using ABAQUS finite elementanalysis software to describe the interaction between the culvert and the soil.Surface-to-surface contact is used to simulate the interaction between the culvert andsoil, in order to close to the engineering actual situation, the culvert should be cut intodifferent sections on the length direction, and taking consideration of the interaction ofthe adjacent culvert sections into the analysis, simulating of the coal seam miningprocess by the MODEL CHANGE function in ABAQUS, then the mined-out area’sinfluence on the structure is calculate base on the finite element model.(4) Based on the different buried depth of goaf， the subsidence and thedeformation law of foundation of the culvert is analyzed，compared with the movingand subsidence curve of surface which are concluded by the existing theory of miningsubsidence forecast income. On the basis of the culvert interaction with the soil，thedifferent location of the culvert’s longitudinal internal force properties and the changerules are analyzed under different working condition.(5) Assess the safety of culvert，for the complex stress state of the culvert，theconcrete strength criterion recommended by the relevant specification is adopted tojudge whether the individual stress larger part to damage state.