Study On Mechanical Properties Of Coal Gasification Slag-Gangue Concrete And Applicability Of Underground Flooring

A large amount of coal gangue will be produced in the process of mine production,and a large amount of coal gasification slag will be produced in the process of coal gasification,these solid wastes will cause waste of land resources and environmental pollution.Underground roadway floor construction requires a large amount of concrete,coal gangue,coal gasification slag to replace the coarse and fine aggregates in concrete preparation of new concrete and applied to mine construction,consumption of a large amount of solid waste,reduce the pollution of the environment,save the mine construction costs.Relying on the actual engineering background of coal mine,this thesis selects coal gangue and coal gasification crude slag from Yangchangwan mine of Ningxia coal industry for research,and also selects crushed stone and sand provided by Yangchangwan mine to study the mechanical properties of coal gangue and coal gasification slag concrete and the applicability of underground flooring.The main research of this thesis is as follows:(1)The basic physical and mechanical properties of coal gangue and coal gasification slag and natural aggregates were compared and analyzed;meanwhile,the chemical composition,mineral composition and microstructure of the aggregates were studied by XRD,XRF and SEM analysis,and the feasibility of using coal gangue and coal gasification slag as concrete aggregates was derived.(2)Using coal gangue and gasified slag to replace natural aggregates in concrete separately to prepare the corresponding coal gangue and gasified slag single replacement concrete,designed a reasonable proportion,carried out concrete cubic compressive strength and flexural strength tests,studied the relationship between the damage form,compressive strength,flexural strength,flexural strength and cubic compressive strength of coal gangue and gasified slag concrete under different replacement ratios,while setting ordinary concrete as a standard control group for comparison,the study found that coal gangue adversely affects the mechanical properties of concrete,while gasified slag can improve the mechanical properties of concrete.(3)Based on the results of the previous tests,the replacement ratio of coal gangue and coal gasification slag in the simultaneous replacement test of coal gangue and coal gasification slag was taken as larger,50%,70% and 100% respectively,while the replacement ratio of coal gangue was 20%,30% and 50% respectively,and the double replacement concrete with 100% replacement ratio of coal gangue and coal gasification slag under different water-cement ratio was set.Slump test,cube compressive strength test,flexural strength test,the study shows that the replacement ratio of gangue is less than 30%,while the gasification slag is higher than 50% of the double replacement concrete performance indicators are better;gangue and gasification slag 100%replacement ratio of double replacement concrete optimal water-cement ratio of 0.6.(4)ABAQUS finite element software was used to establish the three-dimensional finite element models of pavement structure and underground flooring,and the maximum tensile stress and vertical displacement of pavement structure and underground flooring under the action of traveling load were compared and analyzed,and the critical load level of underground flooring and the applicability of double replacement concrete of coal gangue and coal gasification slag were determined,and the effects of axial load size,base layer thickness and surface layer thickness on the mechanical response of underground flooring under static load were analyzed according to the actual situation of the mine.The influence of the mechanical response of the underground flooring under static load,the thickness of the base layer and the thickness of the surface layer were analyzed.(5)The industrial test was carried out in Shicaocun coal mine.The results showed that the field measured strength of the flooring concrete met the requirements and the flooring was poured with good effect;meanwhile,the economic cost analysis of the test section of the roadway was conducted,and the economic savings were obvious considering the savings of aggregate replacement cost and solid waste disposal cost.