赵阳 徐东强

摘要 浅埋偏压小净距隧道结构特殊，两主洞同时施工时掌子面间距的合理选择对隧道稳定性尤为重要。以延崇高速公路头炮隧道为背景，通过ANSYS及FLAC3D软件建立隧道模型并进行数值模拟，采用了双侧壁导坑法先开挖深埋侧隧道的基础上，将规范中建议的小净距隧道施工时掌子面间距为1～2倍洞径的范围细化为4种不同工况，从隧道上部边坡位移、围岩位移及应力、初衬变形及应力、塑性区体积及锚杆受力等方面进行隧道稳定性的分析，最终得到两主洞掌子面保持2倍洞径时施工隧道稳定性最好，可为本工程及相似工程提供参考。

关 键 词 浅埋偏压小净距隧道;数值模拟;掌子面间距;稳定性

中图分类号 U451     文献标志码 A

Abstract Due to the special structure of shallow buried bias tunnel with small span， it is particularly important for the stability of the tunnel to choose reasonable distance of tunnel faces when two main tunnels constructing at the same time. Based on TouPao tunnel on YanQing-ChongLi highway， use ANSYS and FLAC3D to establish the model and take numerical simulation after make sure the tunnel uses both side heading method and deep buried side excavates first， put the distance that 1～2 times of hole diameter range between two tunnel faces of excavation of shallow buried bias tunnel with small span which the standard suggested into 4 situations， analyze the stability of tunnel from displacement of upper slope， displacement and stress of surrounding rock and tunnel lining， volume of plastic zone and stress of bolts， finally it is best for the stability of tunnel to choose 2 times of hole diameter.

Key words shallow buried bias tunnel with small span; numerical simulation; distance of tunnel faces; stability

0 引言

我国经济不断发展，城市建设不断推进，公路、铁路里程数与日俱增，地下工程项目也越来越多。随着交通线路的不断外延扩展，山区地质情况也越来越复杂。因地形、地质或施工等因素的影响，使得隧道线路无法与等高线垂直时，需在靠近边坡且埋深较浅的位置修建隧道，顶部由于地形原因会产生偏壓，此时若隧道两主洞距离小于一定范围，便形成了浅埋偏压小净距隧道。

许多学者对这一形式隧道的相关稳定性进行了研究：张运良等[1]运用ANSYS有限元程序，研究了浅埋偏压小净距隧道在不同偏压角度、间距、埋深条件下，先开挖深埋侧和先开挖浅埋侧2种不同的开挖顺序下的受力和变形特性，得到……