软岩巷道锚杆-拱架联合支护参数优化研究

Study on Combination Supporting Parameters Optimization of Rock Bolting-arch in Soft Rock Roadway

为明确软岩巷道锚杆-拱架支护失效机理,寻求锚杆、拱架支护参数的优化组合,以典型软岩巷道为工程背景,利用具备锚杆破断、拱架压弯屈服与架-岩脱离功能的FLAC3D精细化数值模拟平台,开展了锚杆、拱架不同强度组合对围岩控制效果的对比研究。结果表明:(1)巷道收敛变形量和塑性区体积均随锚杆直径、拱架截面积的增大而减小,但对底鼓的影响不明显;(2)锚杆、拱架单独作用下出现了严重的锚杆破断、拱架屈曲失效现象,二者协同组合作用下效果改善;(3)构件失效机理分析显示拱腿率先变形是拱架整体失效的主要诱因,模拟结果与工程现场基本一致;(4)不同支护强度组合方案对比分析显示,支护效果受锚杆直径的影响并不显著,而随拱架参数的变化响应明显。基于研究结论提出18mm+1.2U36并增设锁拱锚杆的支护优化方案,并得到现场验证。

In order to seek optimal supporting parameters of rock bolt and arch supporting,and verified failure mechanism of rock bolt-arch supporting in soft rock roadway,it taking typical soft rock roadway as engineering background,and refining numerical simulation platform FLAC3 Dwas applied,which include the following characters rockbolt broken,arch bending yield and frame-rock separation,and then comparative studying of surrounding rock control effect by different intensity combination with rock bolt and lagging jack. The results showed that firstly roadway convergence deformation amount and plastic zone area all decreased with rock bolt diameter and lagging jack sectional area increased,but with small influence to floor heaving,the second,seriously rock bolt broken and lagging jack bending yield appeared under independent action of rock bolt or lagging jack,but results improved under synergy action. The third,the main inducing reason of lagging jack failure was lagging jack leg deformation under components failures mechanism analysis. The fourth,according contrastive analysis of different supporting intensity combination,but rock bolt diameters had less influence to supporting results,but obviously with lagging jack parameters variation. The optimization supporting means that 18 mm＋1. 2 U36 with addition arch locking bolts was put forward,and then verified in field.