Abstract

SUN, X. et al. A yielding bolt-grouting support design for a soft-rock roadway under high stress: a case study of the Yuandian No. 2 coal mine in China. J. S. Afr. Inst. Min. Metall. [online]. 2018, vol.118, n.1, pp.71-82. ISSN 2411-9717.  http://dx.doi.org/10.17159/2411-9717/2018/v118n1a9.

The stabilization of roadways in soft rock under high stress has always been a major concern for deep underground coal mines. This paper describes a case study focusing on the stability of a soft-rock roadway in Yuandian coal mine in Anhui Province, China. The Beiyi main return roadway in this mine was primarily supported by U-steel support; however, considerable deformation and severe failures occurred. Therefore, a new support design, the yielding bolt - grouting support design, was proposed based on the physical and mechanical parameters, in situ stress measurements, and the failure characteristics of the roadway. The mechanics of the yielding bolt - grouting support was analysed and compared to the normal bolt - grouting support. A field experiment was conducted in a 100 m long section of the roadway. The monitoring results showed that compared with the old support, the new support design reduced the deformations of roof, floor, and rib by 41.4%, 56.1%, and 64.7% respectively, and the maximum deformation rate decreased from 15.12 mm/d to 9.28 mm/d. This case study indicates that the yielding bolt - grouting support design is an effective method to support roadways in soft rock under high stress.

Keywords : stabilization; soft roadway; yielding bolt; grouting; U-steel support.

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