Study On Self-expanding And Flexible Sealing Filling Material And Its Application For Mine

With the upgrading of energy structure and the popularization of intelligent and unmanned mine in China,the development of new technology and technology has not only brought great economic benefits,but also added new challenges to the safe and efficient mining of mines.The existing mine is seriously damaged under pressure.The risk of coal spontaneous combustion caused by air leakage is increased,which has a great impact on the safety of mining.In order to solve the problems of large amount of traditional sealing materials,low construction efficiency,poor dynamic pressure resistance and poor sealing effect after being compressed,the thesis takes the sealing of No.33 Upper 06 haulage chute in Sancai East area of Nantun coal mine as the research object,with the combination of experimental analysis,numerical simulation and theoretical deduction,the hermetic filling material,hermetic reasonable thickness and construction technology are systematically studied.The main contents are as follows:(1)A kind of flexible filling material for sealing wall(FFM-SW)was developed.The effects of W/C,gypsum-lime ratio(G/L),fly ash content and fiber content on the properties of FFM-SW were analyzed with setting time,fluidity and compressive strength as reference indexes.The results show that:With the increase of W/C,the setting time and fluidity of FFM-SW increase gradually,and the compressive strength decreases gradually.With the increase of G/L,the setting time of FFM-SW decreases first and then increases,and the compressive strength increases first and then decreases.With the increase of fly ash content,the compressive strength of FFM-SW decreases gradually.With the increase of fiber content,the compressive strength increased at first and then decreased at all ages.When the water cement ratio is 1.0,G/L is 80/20,fly ash content is 10%,fiber content is 0.75%,the setting time and fluidity of FFM-SW are moderate,and the compressive strength is high,which can meet the actual needs in the field.(2)A kind of self-expansion and absorb energy of topping material(SEAE-TM)was developed,and its composition and structure were studied.Firstly,the influence of material composition on properties is systematically studied.Secondly,the pore characteristics are studied by the methods of formula calculation,stereological image analysis,probability density function and normal distribution.The results show that:when the water cement ratio is 0.45?0.5,the content of expansion agent is 0.4%?1.0%,and the content of admixture is 1.0?1.5%,SEAE-TM has suitable fluidity,setting time,low density,good expansion ratio and compressive strength.The results of pore characteristics analysis show that:The relationship between the compressive strength and porosity of SEAE-TM can be expressed by exponential function and power function,which is consistent with Ryshkewitch model and Balshin model.The higher the porosity,the lower the density and the lower the compressive strength.The probability density function and normal distribution allow better analysis of the SEAE-TM average aperture and aperture distribution.The smaller the density,the larger the average pore size,the wider the pore size distribution,and the thinner the pore wall,the lower the compressive strength.The results of pore characteristic analysis well explain the macro performance of SEAE-TM.(3)Based on the relevant mechanical knowledge,the model is established and the theoretical thickness of the seal is analyzed.Based on the relationship among compressive strength,shear strength and thickness,and combined with the actual situation in the mine,the theoretical thickness of No.33 Upper 06 haulage chute in Sancai East area of Nantun coal mine is calculated approximately to be 2 m.Using FLAC^3Dsoftware to simulate and analyze the sealing thickness,through the analysis of the law of stress field,displacement field and plastic field,the reasonable thickness of the sealing wall is 2m.The results of theoretical analysis are in good agreement with those of numerical simulation.(4)In this thesis,two methods of formwork support,using modified EPS module and using flexible mould bag,are proposed.Through comparing the advantages and disadvantages of the two,combined with the actual situation of No.33 Upper 06haulage chute in Sancai East area of Nantun coal mine,the flexible mould bag is finally chosen to build the template.Through the hanging of the mould bag and the arrangement of the pulling anchor rod,the filling bearing space of the airtight filling material is formed,and the rapid formwork support of the pouring space before the airtight filling construction is completed.Finally,the site construction process design is carried out.