Abstract: With the rapid development of the construction of highway tunnel in China, there are more and more multi-arched tunnels. Multi-arched tunnel is usually used in the construction of middle and short length tunnels, and there usually appears the problems of unsymmetrical pressure and unfavorable geological. Number 2 tunnel in Chadao of Zhang-Shi highway is 188 m long, which is a double-arched tunnel. The grade of surrounding rock mainly is in grade IV or grade V. There are fragmentation, unsymmetrical pressure and lower imbedding phenomena in surrounding rock of tunnel’s entrance, which increases the difficulty of construction. By the approach of scene monitoring and numerical simulation, the displacement and distortion of surrounding rock with unsymmetrical pressure and lower imbedding are analyzed, after the tunnel is caved. As the result indicating, the outcomes of two analysis methods are accordant by and large. So the numerical simulation method is feasible in analysis of tunnel construction. At the same time, the gap of monitoring method whose prediction is poor is also supplied.

Key words: double-arch, tunnel of highway, lower imbedding and unsymmetrical pressure, dynamic monitoring, numerical simulation.

摘要： 随着我国公路隧道建设的蓬勃发展，连拱隧道的修建也越来越多。连拱隧道一般应用于中短隧道工程，常常存在浅埋偏压、地质条件较差等问题。河北省张石高速公路岔道2号隧道全长188m，属于双连拱隧道。围岩级别主要由IV、V两级构成，进口段围岩比较破碎，埋深较浅同时具有偏压现象，给施工带来了一定难度。本文采用现场监测与数值模拟两种手段，对隧道浅埋偏压段围岩开挖后的位移变形进行了分析研究。研究结果表明两种分析结果基本吻合，可见采用数值模拟方法在隧道工程分析上是可行的，同时也弥补了单一的现场监测方法存在的预见性较弱的缺陷。

关键词: 双连拱, 公路隧道, 浅埋偏压, 动态监测, 数值模拟