Experimental Study And Application Of Cementitious Materials Of Modified Filling Of Granular Solid

With the fast development of economy,the requirement for resource is also intense,especially the coal,the situation of resource shortage is also gradually obvious.Therefore,it is very important to improve coal mining rate and liberate the coal resource for development.Solid filling technology is a way to actively protect the ecological environment,which can effectively protect the upper cascade layer,reduce surface sinking.This paper is based on solid backfilling and coal mining as a background in Xi Shan Coal Electricity Dong Qu Coal Mine,based on the entire use of solid waste,cementitious material is explored to improve strength of solid filling,it can reduce the expense of solid filling,and optimize the technology of solid filling.Base on the laboratory conditions,the particle size grading of the gangue is optimized,it can reduces the compression ratio of filling body under overburden strata loading,and the best matching of cementitious material is obtained through experimental design,it provides data support for industrial applications.Finally,the automatic batching system is designed to further liberate productivity,enhance work efficiency.Application shows that the cementitious material is used for solid filling to better control surface sinking.The achievement of this thesis are as follows:(1)Getting mechanics performance by analyzing the physicochemical properties of the gangue,its particle size is designed after the primary crushing.by analyzing the stress-strain curve of and the compression ratio of different grading scheme,the optimal particle size grading of the gangue(0?10mm:10?30mm:30?40mm=3:6:1)is obtained.In this case,the internal structure of the gangue is tightest.(2)Chemical components of different cementitious material are analysed,major hydration products and microstructure of cementitious material are analyed through XRD spectrum analyzer and SEM scanning electron microscope.C-S-H gel and Ettringite(AFt)play a role in gelling,it is the key to the strength of filling body,and the internal structure becomes more tight with the longer curing time.(3)Slag powder is used to design orthogonal experimental,supplemented a small amount of silicate clinke and desulfurized gypsum.The stress-strain curve relationship of backfill is obtained through uniaxial compressive test,the best matching of cementitious material is obtained,the best matching is that slag powder: silicate clinke:desulfurized gypsum is 70:25:5.the strength of 7d and 28 d of filling body is 3.48 Mpa and 5.11 MPa respectively.(4)System is designed to accomplish multi-source mixture and automatic batching,the practicality of the cementitious material and system are verified through industrial applications.The effect of application,the data of working resistance of hydraulic support and ground sinking are analysed.it indicates that the cementitious material is advantageous in improving filling efficiency and roof managment,and its technique is simplified.