Meikuang Anquan (Nov 2023)
Study on overburden movement law and ground pressure behavior in fully mechanized top coal caving face under the disturbance of upper coal seam
Abstract
In recent years, most of the coal mines in Zhungeer Coalfield have entered the mining of the second main coal seams, such as 6#, 10# and 11#, with an average thickness of more than 10 m, so most of the coal mines use fully mechanized caving mining technology for mining. Affected by the mining of the upper coal seam, the overburden movement, ground pressure appearance and roof weighting source of the lower fully mechanized top coal caving face are more complex. In this paper, the laws of overburden movement and ground pressure appearance of the fully mechanized top coal caving face under the disturbance of the upper coal seam are studied; taking Huangyuchuan 226 upper 02 fully mechanized top coal caving face as an example, by using the methods of theoretical analysis, similar simulation and field measurement. The main conclusions are as follows: before the middle rock stratum is not completely broken, the overburden is characterized by layered collapse, the damage scope develops upward in a stepped manner, and the lower fully mechanized top coal caving face appears small periodic weighting with large weighting step distance and small strength; when the middle rock stratum is completely broken, the damaged areas of the two coal seams will be connected, the overburden will sink in a large range of steps, and the lower fully mechanized top coal caving face is prone to sudden changes in rock pressure such as frame pressing and roof fall; after the middle rock stratum is completely broken, the overburden appears a “bench beam” structure, and the fracture boundary cracks are increasing, the lower fully mechanized top coal caving face appears large periodic weighting, and the weighting step decreases and the strength increases. At the same time, through the research on the movement law of overburden, the source of roof weighting under the upper coal seam disturbance is analyzed, and the calculation method of support load is determined. Taking Huangyuchuan 226 upper 02 fully mechanized top coal caving face as an example, targeted comprehensive control measures such as controlling mining height and increasing support working resistance are formulated, which have achieved good control effect after on-site implementation.
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