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Shock and Vibration
Volume 2015 (2015), Article ID 452479, 14 pages
http://dx.doi.org/10.1155/2015/452479
Research Article

Failure Mechanism Analysis and Support Design for Deep Composite Soft Rock Roadway: A Case Study of the Yangcheng Coal Mine in China

1State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, China
2College of Mining and Safety Engineering, Shandong University of Science and Technology, Qingdao 266590, China

Received 7 April 2015; Revised 29 May 2015; Accepted 3 June 2015

Academic Editor: Alicia Gonzalez-Buelga

Copyright © 2015 Bangyou Jiang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper presented a case study of the failure mechanisms and support design for deep composite soft rock roadway in the Yangcheng Coal Mine of China. Many experiments and field tests were performed to reveal the failure mechanisms of the roadway. It was found that the surrounding rock of the roadway was HJS complex soft rock that was characterized by poor rock quality, widespread development of joint fissures, and an unstable creep property. The major horizontal stress, which was almost perpendicular to the roadway, was 1.59 times larger than the vertical stress. The weak surrounding rock and high tectonic stress were the main internal causes of roadway instabilities, and the inadequate support was the external cause. Based on the failure mechanism, a new support design was proposed that consisted of bolting, cable, metal mesh, shotcrete, and grouting. A field experiment using the new design was performed in a roadway section approximately 100 m long. Detailed deformation monitoring was conducted in the experimental roadway sections and sections of the previous roadway. The monitoring results showed that deformations of the roadway with the new support design were reduced by 85–90% compared with those of the old design. This successful case provides an important reference for similar soft rock roadway projects.