School of Mine Safety, North China Institute of Science and Technology
School of Energy and Mining Engineering, China University of Mining and Technology-Beijing
Department of Civil Engineering, The University of British Columbia, Vancouver

针对深部软碎煤体巷道围岩大变形破坏的控制难题，以某矿围岩控制难度极大的深部软碎煤体孤岛工作面留小煤柱沿空掘巷为工程背景，分析了煤体巷道围岩控制的主要难点；基于FLAC3D数值模拟软件研究了留小煤柱掘巷围岩大变形破坏机制。结果表明：大采高工作面回采扰动引起围岩应力调整卸荷后，掘巷上覆顶板荷载主要由实体煤帮承载，得出留小煤柱掘巷围岩应力峰值区主要位于实体煤帮及其肩角深处，其垂直应力集中系数高达3.04，阐明了掘巷实体煤帮顶板肩角、煤柱帮及实体煤帮浅部塑化围岩是关键控制区域。明晰了留小煤柱掘巷稳定后顶板、实体煤及其煤柱帮塑性破坏区的延伸宽度最大分别为5.88、2.50、3.00 m，揭示了掘巷围岩分区域非对称破坏机制。分析阐明了掘巷支护设计时需将锚索等支护构件的锚固基础位于围岩深部较完整弹性区内，基于此提出了锚梁网支护+槽钢锚索加固+注浆改性等分区域联合支护技术，通过现场工程实践证实采取高强度支护加固技术及注浆改性措施有效改善了深部煤岩体软碎且易发生大变形破坏的留小煤柱掘巷围岩应力状态，试验段掘巷顶板及两帮围岩变形量均控制在500 mm以内，保障了大采高工作面的安全有序回采，为此类深部软碎煤体巷道围岩大变形的有效控制提供可靠途径。

Aiming at the problems of controlling the large deformation and failure of surrounding rock of deep soft-broken coal roadway, the gob-side entry driving with narrow coal pillar in the working face mined on both sides of the deep soft-broken coal seam in a mine is taken as the engineering background, which is very difficult to control the surrounding rock. The main difficulties of surrounding rock of coal roadway control are analyzed, and the large deformation and failure mechanisms of surrounding rock of gob-side entry driving with narrow coal pillar are studied in FLAC3D numerical simulation software. The results show that the stress adjustment and unloading caused by the mining disturbance at the large height working face, the overlying roof load of gob-side entry driving is mainly borne by the solid coal. It is concluded that the peak stress area of surrounding rock in gob-side entry driving with narrow coal pillar is mainly located in solid coal and its depth of shoulder angle, and its vertical stress concentration factor is as high as 3.04. It is clarified that the roof shoulder angle in solid coal, coal pillar and the shallow plasticized surrounding rock in solid coal are the key control areas. It is characterized that the maximum extension range of plastic zone of roof, solid coal and coal pillar is about 5.88 m, 2.50 m and 3.00 m respectively, and the sub-regional asymmetric failure mechanisms of surrounding rock in gob-side entry driving with narrow coal pillar are revealed. The analysis clarified that the anchoring foundation of anchor cables and other supporting components should be located in a relatively complete elastic zone in the deep part of surrounding rock during roadway support. Based on this, the sub-regional combined support technology of anchor beam mesh support + channel steel anchor cable reinforcement + grouting modification is proposed. Engineering practice has proved that the high-strength support reinforcement and grouting modification measures have effectively improved the stress state of surrounding rock in gob-side entry driving with narrow coal pillar in deep coal rock mass that is soft, broken and prone to large deformation and failure, and the deformation of the roof and two sides of gob-side entry driving in the test section are controlled within 500 mm. It ensures the safe and orderly mining of the working face with large-mining height and provides a reliable way for the effective control of the large deformation of surrounding rock in such deep soft-broken coal roadway.

国家自然科学基金面上资助项目（52074296）；国家自然科学基金青年科学基金资助项目（52004286）；国家留学基金资助项目（202106430003）

王　恩，谢生荣，陈冬冬，等. 深部孤岛工作面留小煤柱掘巷围岩破坏机制与控制[J]. 煤炭科学技术，2023，51（11）：41−50.

WANG En，XIE Shengrong，CHEN Dongdong，et al. Failure mechanism and its control of surrounding rock for gob-side entry driving with narrow coal pillar in the working face with goaf on both sides[J]. Coal Science and Technology，2023，51（11）：41−50.