Mechanisms And Control Technology for Roof Caving of a Roadway in a Fold Belt in Zhaogu No.2 Coal Mine, Jiaozuo City, Henan Province, China
Authors
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School of Energy and Mining Engineering, China University of Mining & Technology, Beijing 10083 ,CN
Gao Xu
Keywords:
Fold structure, plastic zone, numerical simulation, mechanism of roof caving, control technologyAbstract
To prevent the roof caving of a mining roadway in the No.2[1] coal seam in Zhaogu No.2 coal mine, Jiaozuo city, Henan province, China, we analysed mechanisms of roof caving of the roadway in geological tectonic belt in the coal mine by using comprehensive research methods, such as theoretical analysis, numerical simulation, and field testing. The results demonstrate that: (1) the No.2[1] coal seam contains fault and fold structures and its bidirectional pressure ratio can reach about 3, which affects the shape and extent of the plastic zone in the roadway. (2) Based on the theory of a butterfly-shaped failure zone and numerical simulation, the shape of the plastic zone in the roadway is analysed. It is found that, when the plastic zone in surrounding rock of the roadway presents a butterflyshaped distribution, large deformation occurs in the roadway when wings of the butterfly-shaped failure zone are just located in roof, floor, and two side walls of the roadway. (3) Due to the significant changes in the plastic zone, anchor bolts are not long enough and anchor cables with limited elongation fail to support the roadway. Therefore, a scheme using long anchor bolts is proposed. The connected long bolts underwent significant elongation and are able to provide a continuous supporting force. This controls the deformation of surrounding rock, thus achieving good supporting effect.
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