文章以乌蒙山二号四线铁路车站隧道为工程依托,采用数值模拟手段,对多部开挖隧道系统锚杆的非均衡支护进行了研究。结果表明:在均衡支护条件下,系统锚杆轴力呈现“拱肩(①、②部)〉拱脚(④、⑤部)〉边墙(⑥、⑦部)〉拱顶(③部)”的分布,部位不均衡性显著;拱脚、边墙部位的锚杆轴力左右不对称现象也很显著,具体表现在先挖侧大于后挖侧;拱顶的锚杆轴力很小,几乎未起作用。通过分别改变锚杆长度、间距和直径,进行系统锚杆非均衡支护分析,并与均衡支护工况相比,单环节省锚杆用量分别为37%、36%和36.93%,经济效益显著。
Using the four-track Wumengshan No.2 railway station tunnel as an example, a numerical simulation was performed to study nonuniform support of the system anchor bolts adopted in a multi-partition excavation. The results indicate that: under uniform support of the system anchor bolts, the order of axial force magnitude is "spandrel (partition (1) and (2)) 〉 arch springing (partition (4) and (5) 〉 sidewall (partition (6) and (7) 〉 crown (partition (3)," with obvious nonuniformity at different excavation partitions; the axial force on the left and right sides of the anchor bolts at the arch springing and sidewall are asymmetrical, i.e., it is larger at the former exca- vated side than it is at the latter one; the axial force of the anchor bolts is minimal at the crown and has almost no effect. An analysis of nonuniform support of the system anchor bolts is carried out based on different lengths, diameters, and intervals of anchor bolts, and comparison is undertaken with the uniform support. Based on the re- sults, consumption of the anchor bolts is 37%, 36%, and 36.93% of the original consumption at the spandrel, arch spring, and sidewall and crown, respectively, thereby achieving significant economic benefits.