Geotechnical Engineering

Pillar width determination and surrounding rocks control of gob-side entry with large cross-section and fully-mechanized mining

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  • College of Resources & Safety Engineering, China University of Mining & Technology (Beijing), Beijing 100083, China

Received date: 2015-08-31

  Online published: 2018-06-09

Supported by

This work was supported by the National Natural Science Foundation of China (51234005) and the Fundamental Research Funds for the Central Universities (2010YZ02).

Abstract

To improve the coal recovery rate, it is crucial to properly determine the coal pillar size, supporting patterns and parameters of the roadway, since this can ensure the stable of butt entry with fully-mechanized mining. The evolution of principal stresses, deformation and failure are studied using FLAC3D with different pillar widths in haulage roadway 20103 of Wangjialing coal mine. It is shown that the most reasonable and economic pillar widths range from 6 m to 10 m. The final reasonable pillar width is determined to be 8 m based on the geological production conditions. Theoretical analysis and borehole observation show that the main roof breaks at 7 m next to the gob. The property and structure of the surrounding rock and the stress distribution are asymmetric along the axis of roadway, resulting in asymmetric roof strata behaviors including the subsidence of roof near the pillar and even the dislocation, embedding, step convergence of rock on the abutment of coal mine. The roof near the pillar and the abutment of coal mine are the key positions of deformation failure. A comprehensive supporting technology is proposed including high strength anchor-beam-net, asymmetric cable-beam and cable truss. The mechanism of supporting measures for surrounding rock is analyzed. It is shown that the pillar width with 8 m is reasonable and the proposed measure can control the asymmetric deformation failure. The proposed supporting measure has been successfully applied to Wangjialing mine area.

Cite this article

ZHANG Guang-chao, HE Fu-lian . Pillar width determination and surrounding rocks control of gob-side entry with large cross-section and fully-mechanized mining[J]. Rock and Soil Mechanics, 2016 , 37(6) : 1721 -1728 . DOI: 10.16285/j.rsm.2016.06.024

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