Ground response and failure mechanism of gob-side entry by roof cutting with hard main roof

Abstract

This study is the result of long-term efforts of the authors’ team to assess ground response of gob-side entry by roof cutting (GSERC) with hard main roof, aiming at scientific control for GSERC deformation. A comprehensive field measurement program was conducted to determine entry deformation, roof fracture zone, and anchor bolt (cable) loading. The results indicate that GSERC deformation presents asymmetric characteristics. The maximum convergence near roof cutting side is 458 mm during the primary use process and 1120 mm during the secondary reuse process. The entry deformation is closely associated with the primary development stage, primary use stage, and secondary reuse stage. The key block movement of roof cutting structure, a complex stress environment, and a mismatch in the supporting design scheme are the failure mechanism of GSERC. A controlling ideology for mining states, including regional and stage divisions, was proposed. Both dynamic and permanent support schemes have been implemented in the field. Engineering practice results indicate that the new support scheme can efficiently ensure long-term entry safety and could be a reliable approach for other engineering practices.

Keywords

gob-side entry by roof cutting / ground response / failure mechanism / following mining states control / hard main roof

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