软岩巷道锁拱锚杆精细化数值模拟研究

Study on Fine Numerical Simulation of Arch-locking Bolt in Soft Rock Roadway

锁拱锚杆是软岩巷道支护中拱架失效的常用防控措施,但是其参数设计缺少依据。为研究锁拱锚杆位置、长度参数对巷道支护效果的影响规律,以典型软岩巷道为工程案例,采用自主开发的锚杆-拱架联合支护精细化模拟技术开展了数值模拟试验。结果表明:无锁拱方案围岩变形量大,拱腿率先变形,随后与围岩分离,最终导致支护体系失效;而锁拱锚杆控制了拱腿内弯变形且防止了拱架与围岩分离,保证了支护体系的完整性,支护效果明显改善;巷帮内移量和塑性区体积随锁拱点高度H的增加呈现先减小后增大的规律且影响显著,支护效果随锁拱锚杆长度L的增大趋好但并不明显。基于研究结论确定了锁拱锚杆优化参数(H=1.0 m,L=3.0 m),现场实践表明效果良好。

Locking bolts are frequently used to control the failure of the supporting arch in soft rock roadway support system,but the design basis of the locking bolts parameters is not clear.In order to investigate the roadway support effect influenced by the position and length of the arch-locking bolt,based on a typical soft rock roadway engineering case,numerical simulation experiments were carried out through an improved numerical simulation approach.The results indicate that:roadway supported without locking bolts deformed seriously,and the arch legs’inward bending deformation and arch-rock separation were the breakthrough of the overall failure of the support system;the arch-locking bolts suppressed the arch legs inward bending deformation and prevented arch-rock separation,which ensured the integrity of the support system,and the final supporting effect was improved significantly;the deformation value and plastic zone volume both first decrease and then increase with the increasing of the locking bolt height H,and the impact was significant;the support effect tends to be better but not obvious with the increasing the arch-locking bolt length L.Based on the research conclusions,the optimized parameters of the lock arch bolt(H=1.0 m,L=3.0 m)were determined,and the field practice showed the optimization scheme works well.