| The feature of fully mechanized caving itself determines that caving coal process will inevitably lose some coal, so it has great significance to research of coal and rock caving law and coal caving technological parameters to improve caving coal recovery. Comprehensive research means including theoretical analysis, numerical simulation, similar material test and industrial experiment are used in this paper to study the overburden movement rules and caving coal technological parameters under the condition of fully mechanized caving mining.Through theoretical analysis, assessment methods and influencing factors influencing top coal caving property are obtained. UDEC is used to analyze the effect of different mining heights to the advance pressure in top coal and bottom coal, and the different mining height peak stress and position are obtained. Proper mining height is determined with the overburden stress behavior. Considering the peak stress and security support comprehensively, the reasonable mining height of the face is determined. Using the means of discrete element software to research overburden strata movement rules of top coal caving face, the existence of arch structure above goaf, and main roof in the arch structure forming transfer rock beam are confirmed. Through similar material experiment method, the coal rock caving and flowing laws are obtained. With the statistics of recovery and rate of gangue,0.8m is determined as the reasonable coal drawing pace. The caving effect of different caving methods is analyzed with the application of PFC2D soft, and the optimal caving method of one round caving in order is selected based on the results. A new method of improving recovery of top coal in primary mining is put forward. The industrial experiment is conducted in 1301N face with the research conclusions, and good production and social effects are obtained, which verifies the rationality of the research. |
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