中文摘要：

山岭隧道下穿既有道路时,不确定因素多,在施工过程中易发生安全风险事件。为降低和控制施工风险,有必要对下穿既有道路施工风险进行评估。以新建的关林子公路隧道下穿既有公路为工程背景,参考风险管理方法,采用专家调查法和层次分析法对工程施工阶段风险进行辨识、分析、评价,得到掌子面失稳为最大施工风险,围岩条件和支护参数对施工风险影响最大。根据得出的风险评估结果,提出严格控制爆破尺寸,加强监控量测等风险控制措施,为关林子隧道安全施工提供保障。

英文摘要：

There are a variety of uncertain factors when the tunnel under pass the existing roads, it is liable to security risk event under its construction. In order to reduce and control the risk, it is necessary to assess the risk especially when the tunnel under pass existing roads. This research took the Guanlinzi Highway tunnel which under pass an existing road as an example, based on risk management approach, this paper adopted the expert investigation methods and analytic hi- erarchy process to identify, analyze and assess the risk during the process of tunnel construction, the results as the tunnel face instability is the most dangerous risk, wall rock conditions and support parameters has the largest impacts. Based on the risk assessment results obtained, suggestions were strictly controlled blasting sizes, strengthen monitoring and measurement and other risk control measures should be taken to provide protection for Guanlinzi Tunnel construction.