针对留大煤柱采出率低和留小煤柱护巷矿压显现剧烈存在的矛盾，采用矿压理论分析、FLAC3D数值模拟和巷道变形现场实测，对潞安集团阜生煤矿6 m大采高留小煤柱切顶卸压沿空掘巷机理与围岩控制进行了研究，得到:① 切顶卸压可人为控制基本顶的断顶位置，实现压力主动调控，切顶后，改变了基本顶原有应力传递路径，压力有效转移至采空区，减轻了采空区侧向实体围岩应力，沿空掘巷围岩应力更加均匀缓和;② 切顶后顶板断裂结构发生变化，由初次来压前基本顶四边固支变为三边固支，由初次来压后基本顶三边固支变为两边固支，垮落步距相应降低，顶板更易于垮落，切顶工作面的矿压显现也相应得到缓和;③ 切顶角度、切顶深度、切顶孔间距、切顶孔布置方式是实现精准切顶卸压的关键，16 m切缝深度恰能切断石灰岩基本顶，可有效缩短基本顶侧向悬臂长度，同时充分发挥采空区垮落矸石的碎胀支撑作用;④ 3种情况下的数值模拟显示，传统留25 m煤柱尺寸过大，造成大量资源浪费，且峰值压力较大，为18.2 MPa;仅留8 m小煤柱但不切顶时小煤柱所承受支承压力最大，峰值可达19.3 MPa，可能导致掘巷失败;切顶8 m小煤柱条件下的煤柱及其附近围岩塑性区范围最小，且小煤柱支承压力最小，峰值为12.7 MPa，采空区应力提高到0.11 MPa;结合切顶卸压，实现了对围岩压力的主动调控;⑤ 实践表明，采用切顶卸压和配套合理支护技术可实现小煤柱沿空掘巷在迎采阶段和本工作面回采阶段围岩稳定，为类似条件矿井安全高效开采提供借鉴和参考。

In view of problems existing in large coal pillars and small coal pillars for roadway maintenance,theoretical analysis,numerical simulation and field measurement are used to study gob-side entry developed by roof cutting for destress and surrounding rock control in Fusheng Coal Mine with a large mining height of 6 m.Following conclusions are obtained:① Position of main roof fracture can be artificially determined by pressure relief with roof cutting realizing the active pressure control.After roof cutting,the original stress transfer path of the main roof is transformed,the pressure is effectively transferred to the gob,reducing the abutment pressure and avoiding excessive stress from transferring to the solid surrounding rock,gob side entry surrounding rock stress is more uniform and gentler;② Roof fracture structure changes after the roof is cut,before the first weighting,the fixed sides of the main roof change from four to three.After the first weighting,the fixed sides of the main roof change from three to two.The collapse interval is correspondingly reduced.The roof is more likely to collapse.The pressure of the working face also appears gentler;③ Cutting angle,cutting depth,cutting hole space and layout are the keys to the precise roof cutting.A 16 m cutting depth can cut off the main roof of limestone,which can effectively reduce the length of overhanging roof of main roof,cut off the continuous stress.Also,this makes a full use of the bulking and support capacity of caved rocks in the gob;④ Numerical simulations under the three conditions show that the traditional coal pillar of 25 m is too large,causing a lot of waste of resources,and the peak pressure is 18.2 MPa.The supporting pressure of the pillar is the largest with a peak value of 19.3 MPa if only a 8 m of small coal pillar is used without roof cutting,which may lead to failure of gob side entry.The plastic zone of the coal pillar and its surrounding rock under the condition of a small coal pillar of 8 m with roof cutting is the smallest,and the supporting pressure of the small coal pillar is the smallest with a peak value of 12.7 MPa,and the goaf stress is increased to 0.11 MPa.Combined with cutting roof pressure relief,the active control of surrounding rock pressure is realized;⑤ Mine site practice shows that pre split roof cutting and support technology can ensure the stability of surrounding rock during the heading phase and the mining phase along the gob.This study provides a reference and support for the safe and high efficiency mines under similar conditions.

1 工程背景

2 留小煤柱切顶护巷机理

3 切顶施工参数与工艺

   3.1 切顶参数与钻孔施工

   3.2 102工作面爆破施工巷道支护

   3.3 定向预裂爆破工艺

4 留小煤柱切顶护巷数值模拟

5 巷道围岩控制方案和效果

   5.1 巷道支护方案

   5.2 实施效果

6 结论