基于数值分析与现场试验的破碎带支护参数优化

Parameters Optimization of Fracture Belt Support Based on Numerical Analysis and Field Test

为了控制围岩的变形,确保施工的安全,结合船顶隘隧道在穿越断层破碎带时出现的变形过大,局部出现塌方的现象,提出了减小钢拱架间距增加初支强度的支护方案,并选取了两组方案进行对比分析研究。先通过数值模拟对钢拱架和锚杆分别进行了计算,然后在现场监测试验中,选取了两组试验段,对两种不同的支护参数下的围岩变形、喷射混凝土压力、钢拱架应力以及初支围岩压力进行现场监控量测,验证了支护优化的可行性。研究表明:在断层破碎带初支参数优化中,锚杆支护效果不理想,而钢拱架的作用明显,对围岩大变形起到了良好的控制作用。由此可知通过加密钢拱架来增加初支强度,适当弱化锚杆来减少工序,降低成本的支护优化措施在隧道穿越断层破碎带中是可行的。

In order to control the surrounding rock deformation and ensure the construction safety, combined with the phenomena that excessive deformation and local collapse appeared when Chuanding ＇ ai Tunnel crossed the fault fracture zone, the supporting scheme that steel arch frame spacing was decreased with the increase of primary support strength was proposed. And two groups of programs were selected to carry out the comparative analysis research. Firstly, the steel arch and bolt were calculated respectively by numerical simulation;secondly, in the field monitoring experiment, two groups of test sections were selected; thirdly, the surrounding rock deformation, pressure jet concrete, steel arch stress and initial supporting surrounding rock pressure were monitored and tested on site with two different branch supporting parameters, which verified the feasibility of the support optimization. The research shows that in the primary support parameter optimization of fault fracture zone, the supporting effect of bolting is not ideal, whereas the effect of steel arch is significant, which has a good control effect on the large deformation of surrounding rock. Therefore, it is known that the support optimization measures with concentrating the steel arch support to increase the primary support strength and appropriately weakening the anchor to reduce the process and the cost is feasible when the tunnel crosses through the fault fracture zone.