大断面巷道非均匀变形机理及稳定性控制研究

为探究围岩受采动影响条件下巷道变形破坏与稳定性控制，以桑树坪二号井3309工作面运输平巷为工程背景，采用FLAC3D数值模拟方法分析“一掘二采”期间大断面巷道围岩主应力差分布特征，结合现场试验，揭示大断面巷道围岩非均匀大变形破坏机理，分析提出巷道围岩非均匀变形控制补强支护设计方案。研究结果表明：①一次回采和二次回采期间，巷道煤柱及煤壁两侧煤体峰值应力差分别为7.93MPa、12.96MPa，煤柱帮峰值应力远高于煤壁帮，两侧煤体呈非对称变形破坏特征|②与一次回采相比，二次回采期间3309工作面运输平巷煤柱帮主应力增大11.46MPa，塑性区范围从4.5m增加至煤柱宽度，煤壁帮主应力差增加27.46MPa，塑性区增加1.5m，巷道围岩处于高强度剪应力状态，易引起大变形破坏|③基于大断面巷道两侧煤体非均匀变形破坏特征，针对性提出“一长一短”两种补强支护方案，现场试验后巷道围岩稳定性控制效果良好。

Research on Non-uniform Deformation Mechanism and Stability Control of Large Cross Section Roadway

Aiming at the problem of uneven large deformation and failure of support failure of slabs in the large section roadway caused by bottom pull in the 3309 transportation lane of Sangshuping No. 2 Well, the method of numerical simulation was used to study the surrounding rock of the roadway during mining. The change characteristics of the principal stress difference reveals the non-uniform deformation mechanism of the surrounding rock in the large section of the double-lane working face. The results show that: (1) The peak stress of coal pillar slab during primary mining is 7.93MPa higher than that of coal wall. During secondary mining, the peak stress of coal pillar slab is 12.96MPa higher than that of coal wall. The gang is deformed asymmetrically. (2) During the second mining period, the main stress difference of the 3309 transportation lane coal pillar sill increased by 11.46MPa and the stress concentration factor increased by 1.63 compared to the primary mining period. Compared with the coal wall during one mining period, the principal stress difference increased by 27.46MPa, and the stress concentration factor increased by 3.92. The surrounding rock as a whole was in a state of high shear stress, and the deformation and damage were serious. (3) The use of ?32×2500mm self-tapping bolts for the main side of the 3309 transportation lane, and the use of ?32×3500mm self-tapping bolts for reinforcement and support for the secondary side can achieve a good surrounding rock control effect.