The Experimental Study On Goaf Paste Filling Material Characteristics And The Numerical Simultion Of Filling Mining

Coal mine resource is an extremely important energy resource in China. It is not only a momentous energy in China but the vital indispensable material guarantee of normal economic development and social progress. The energy structure of China is "rich of coal, lean, poor of gas", which decides the important position of coal resource. In the long period, China will maintain this invariant energy production and consumption structure dominated by coal mine. However, the severe "three under" problems of coal is seriously restricting the development of Chinese coal industry. According to incomplete statistics, the amount of "three under" coal mine is about 14Gt. If not effectively resolved, it will shorten the service life of mine, which will not only cause enormous waste of resources for the country, but also bring about the fierce pressure of employment and other issues for coal mining.As an important part of green mining technology, paste filling can not only realize the mining without moving villages, but also effectively control the surface settlement and improve the coal recovery rate, which is the effective mining method of resolving "three under" problems. The strength and the long-term stability of paste filling materials is the key to restrict the surface subsidence of paste filling mining technology.In this thesis, use the method of laboratory experiment to research the paste filling material's raw material properties, filling slurry working characteristics, mechanical characteristics. Take Benxi Caitun mine 801 working face of the paste filling mining as an example and use the FLAC^3D numerical simulation software to simulate the paste filling mining, which has obtained certain main achievements just as the following:?1? Study of the coal gangue and fly ash:By means of screening experiments, the particle gradation of coal gangue is good to meet the requirements of filling aggregate; Use laser analyzer to measure the size of fly ash and results show that the particle size is from 0.46?m to 30.76?m. XRD analysis shows that there is a large amount of vitreous in fly ash, which contributes to the high activity of fly ash. XRF analysis shows that the amount of SiO₂?Al₂O₃ and Fe₂O₃ make up 89.47percent of the total Chemical amount, which can meet the needs of filling materials.?2? Study of the mineral component of cement and the experiment of cement mortar:XRD analysis show that the content of 3CaO. SiO₂ and 3CaO. Al₂O₃ is higher than the normal level, which does the main contribution to the early strength of cement. The experiment of cement mortar test results show that the 28d strength of cement is 40.59MPa and the 3d strength is 16.96MPa, which is the 41.78 per cent of the 28d strength.?3? Experimental study on the working characteristics of paste filling slurry: Under different content of fly ash, cement content, the rate of the fine gangue and concentration conditions and through the determination of paste filling slurry slump, expand degree, stratification and bleeding rate, reflect the working characteristics in paste filling slurry.?4? Experimental study of the mechanical properties of paste filling body:Under different content of fly ash, cement content, the fine rate of gangue and concentration conditions, use the test of the cube compressive strength of paste filling body to reflect the mechanical characteristics in paste filling body. With the increase of the amount of fly ash, cement and concentration, the compressive strength increased; with the increase of fine rate of gangue, strength increased first and then decreased. And the amount of fly ash and cement content has a greater impact on the later strength and the quality of concentration has a significant influence on the early strength of the paste. The fine rate of gangue affects the whole process of the development of paste.?5? Use FLAC^3D and consider the actual geological and mining conditions in Benxi Caitun mine 801 working face of paste filling to establish the numerical model and simulate the surface subsidence to obtain surface subsidence value. Lastly carry out a comparative analysis of the simulation results and the measured results.