Study And Application Of Mechanical Properties Of Gangue Paste Material

Paste filling mining is one of the most important green mining methods.The gangue paste material is mainly composed of reasonably graded coal gangue,which is mixed with cementitious material.It can be added with fly ash and additives to change its performance.In order to master the mechanical properties of gangue gypsum materials systematically and provide reference for the determination of mechanical parameters of filling body in simulation analysis,based on the gangue gypsum materials of Gaohe coal mine,this paper has carried out uniaxial compression,splitting tension,variable angle shear,elastic modulus and Poisson's ratio test tests,and has made statistical analysis on the test results,mainly achieved the following results:(1)Through the orthogonal test,there are totally 54 cubes with dimensions of100 mm × 100 mm × 100 mm,45 cubes with dimensions of 70.7 mm × 70.7 mm ×70.7 mm and 27 cubes with diameter of 50 mm and height of 100 The mechanical properties of mm cylinder gangue gypsum materials are tested.The primary and secondary relations of the influence of mass concentration,fly ash content and cement content on the mechanical properties of gangue gypsum materials are analyzed.The mathematical prediction model of the primary influencing factors of each index and the primary interaction between any two factors is established by response surface analysis.(2)The uniaxial compressive strength,splitting tensile strength,cohesive force and elastic modulus of gangue paste material can be fitted by origin,which has a good functional relationship,and this relationship is less affected by the mass concentration,fly ash content and cement content.(3)21 samples of 70.7mm × 70.7mm × 70.7mm cubic gangue gypsum were prepared for uniaxial compression test,and the evolution rule of the strength of layered gangue gypsum filling material with the increase of age in e1302 working face of Gaohe coal mine was analyzed.(4)Three cubes of gangue gypsum with dimensions of 70.7 mm × 70.7 mm ×70.7 mm,100 mm × 100 mm,150 mm × 150 mm × 150 mm and 200 mm × 200 mm× 200 mm were prepared for uniaxial compression test respectively.The size effect degree and size effect law were analyzed,and the conversion coefficient of uniaxialcompression strength of gangue gypsum with different sizes was obtained.(5)Based on the analysis of the characteristics of the whole stress-strain curve in different stages,the constitutive equation of the whole stress-strain curve is established.(6)By using the prediction model of mechanical properties of gangue gypsum materials,the mechanical parameters of the backfill in e1302 filling mining face of Gaohe coal mine are determined,and the numerical simulation analysis is carried out.The simulation results have certain guiding significance for production practice,and the feasibility of the prediction model of mechanical parameters of gangue gypsum materials is illustrated.There are 55 pictures,47 tables and 88 references in dissertation.