| In the process of mining coal resources,the massive production and improper accumulation of solid waste and coal gangue will not only cause water,air and soil pollution,but also occupy a large amount of land area.The reasonable discharge and comprehensive utilization of coal gangue have become the focus of people.Issues of concern and research;on the other hand,the gradual increase in industrial and agricultural production has led to a large accumulation of solid construction waste.As one of the methods to solve a series of problems such as coal gangue discharge and treatment of construction solid waste,coal gangue The joint treatment with construction solid waste can not only realize waste utilization,reduce costs,but also protect the environment.In this paper,coal gangue from Neijiang Weiyuan Coal Mine was used as a raw material,and a cementitious material was prepared through activation tests.A composite filling material with coal gangue and construction solid waste as the main aggregate was designed.The materials at different ratios were studied through laboratory experiments.Using FLAC3 D to establish numerical models of filling and mining with different filling schemes,analyze the stress and surface settlement of the overburden after filling.The main research processes and results of the thesis include the following:(1)Through the material basic test and microscopic test basic properties are measured for raw materials,raw materials,the active ingredient of coal gangue and filling properties were evaluated,on the basis of the preparation of the coal gangue activation material,analyzes the mechanical,chemical,composite of three methods for activation,increased with the increase of mechanical activation time activation material activities,grinding agent can to a certain extent,can improve activity of raw materials,exciting agent to join has soared to the activity,different activation activity plan and raw material has good correlation,can be used as the basis of a quick evaluation activity.(2)Based on coal gangue activation test results,the design under the different ratio of coal gangue,building solid waste packing material,with different dosage of fly ash,building solid waste replacement rate,mass concentration,content of water reducing agent of the packing material for the flow performance tests,fitting the slump and the extension of the three-dimensional curved surface,established the slump and the expansion degree of 3d model,it can better reflect the packing material when the flow performance,determine the influencing factors of strength: mass concentration> dosage of fly ash>building solid waste replacement ratio > content of water reducing agent.(3)The compressive performance test,splitting tensile performance test and stress-strain analysis of gangue-solid waste filling material are carried out.The addition of solid waste is negatively correlated with the strength of the filling material,while other factors are positively correlated with the strength in the range of proportion.The influence of surface deformation and settlement is also discussed.(4)In view of the hydration process evolution of gangue-solid waste backfill materials,the selected backfill materials were tested with microscopic morphology,X-ray diffraction and phase analysis,and the interaction between composite materials was analyzed.Based on the hydration dynamic model,the hydration law of backfill materials was studied.(5)FLAC3D is used to discuss the overburden stress,surface deformation and surface subsidence of the mining area under different filling schemes.With the addition of backfill body,the surface deformation and maximum subsidence of the mining area decrease.The suitable backfill mining scheme can make the mining more reasonable,economical and safe. |
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