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Coal Engineering ›› 2026, Vol. 58 ›› Issue (6): 95-103.doi: 10.11799/ce202606013

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Roof subsidence control in gob-side entry retaining for shallow medium-distance coal seams #br#

  

  • Received:2025-10-15 Revised:2026-01-28 Online:2026-06-15 Published:2026-06-24

Abstract:

In order to solve the problem of controlling roof shear-induced subsidence and surrounding rock stability during gob-side entry retention in shallow, medium-close distance coal seams, this study investigates the 42305 working face of Wanli No. 1 Mine. Based on borehole imaging results and analysis of the overlying strata structure, the primary causes of extensive roof weighting and shear-induced subsidence along the rib were identified. Accordingly, a structural mechanical model for gob-side entry retention in shallow, medium-close distance coal seams and a simplified rock beam mechanical model for the interlayer key stratum were developed. Theoretical calculations determined that the maximum bending moment and shear force in the overlying strata of the retained entry are 14773.5 kN·m and 6009.58 kN, respectively. Analysis of the overlying strata structure and rock mechanical properties indicates that failure primarily occurs in the shallow weak rock layers. Therefore, a combined strategy of "grouting reinforcement" and "U-shaped steel sets with anchor cable suspension beams" was proposed to enhance the existing support system. These measures improved the shear resistance of the shallow weak rock layers to 6111.68 kN. Field monitoring results demonstrated a significant reduction in the roof subsidence rate, with a maximum stabilized subsidence of 195 mm, confirming effective control of the shear-induced subsidence. This study offers a practical reference for managing roof shear-induced subsidence and surrounding rock stability in gob-side entry retention under similar engineering and geological conditions.

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