浅埋大跨小净距桃花峪黄土隧道系统锚杆作用效果研究

为了更好地研究系统锚杆在浅埋大跨小净距黄土隧道中的支护效果,以武西高速公路桃花峪隧道施工为依托,进行有无锚杆现场对比试验,结果表明:从初期支护左右侧拱顶沉降的对比来看,有锚杆段沉降略小于无锚杆段,水平收敛相差不大,锚杆对改善隧道围岩和初期支护受力作用相对较小,有锚杆试验段围岩-初期支护接触压力量值相对较小,相比于无锚杆段的土体压力略微均匀。综上所述,建议取消锚杆,对于薄弱环节可保留先行洞边墙小净距侧的锚杆施作。

Study on Effect of Systematic Anchor Bolts in Construction of Shallow-covered Large-span Small-spacing Loess Tunnels:Case Study on Taohuayu Tunnel

In this paper, comparison and contrast is made between field trials in tunnel sections with anchor bolts and those in tunnel sections without anchor bolts, with Taohuayu shallow covered large span small spacing loess tunnel as an example, so as to study the supporting effect of systematic anchor bolts. The results show that: 1) The crown settlement of primary support in tunnel sections with anchor bolts is slightly smaller than that in tunnel sections without anchor bolts; 2) The effect of anchor bolts to improve the stress condition of the surrounding rock and primary support of the tunnel is insignificant; 3) The contact pressure between the surrounding rock and the primary support in tunnel sections with anchor bolts is smaller and more uniform than that in tunnel sections without anchor bolts. The authors suggest that the anchor bolts should be cancelled, while the anchor bolts on the sidewall of the proceding tunnel close to the small spacing may be kept so as to ensure the successful tunneling through weak zones. The paper can provide reference for the design and construction of similar shallow covered large span small spacing loess tunnels in the future.