盾构下穿既有桥梁风险识别及防控方案评价

Evaluation of Risk Identification and Prevention and Control Scheme of Shield Tunnel under Existing Bridge

地铁隧道与既有桥梁交叉的情况愈来愈多,因此保证盾构隧道下穿施工过程中既有桥梁的稳定是此类工程的基本目标。盾构隧道下穿既有桥梁的稳定性以及保障方案的选择是非常重要的研究课题,其研究方法由工程经验逐渐向理论方向拓展、由传统理论方法向新技术新理论发展、由最开始的定性或定量的单一方法向定性和定量多层次方法发展。因此,用较简单的测试手段来提高盾构隧道下穿既有桥梁的稳定性并选择合理有效的措施进行保护就尤为重要。文章基于层次分析理论,采用一种定性与定量相结合的多层次分析方法对盾构下穿既有桥梁的稳定性保障方案进行研究。该方法不仅考虑了隧道施工、地层变形、既有桥梁基础等这些非确定性因素,而且针对这些影响因素所提出的解决方案进行合理的排序,在施工中可以选择合适有效的方法对桥梁的安全运营提供保障。

There are more and more intersections between subway tunnels and existing bridges, so ensuring the stability of existing bridges in the process of shield tunnel construction is the basic goal of this kind of engineering. The stability of shield tunnel under the existing bridge and the choice of guarantee scheme are very important research topics. Its research method is gradually expanded from engineering experience to theory, from traditional theory to new technology and new theory, from the initial single qualitative or quantitative method to qualitative and quantitative multi-level method. Therefore, it is particularly important to use simple testing methods to improve the stability of the shield tunnel passing through the existing bridge and choose reasonable and effective measures for protection. Based on the analytic hierarchy process theory,this paper uses a qualitative and quantitative multi-level analysis method to study the stability guarantee scheme of the shield under the existing bridge. This method not only considers the uncertain factors such as tunnel construction, stratum deformation and existing bridge foundation, but also makes a reasonable ranking of the solutions proposed according to these influencing factors. in the construction, appropriate and effective methods can be selected to ensure the safe operation of the bridge.