软岩浅埋隧道锚开挖方案比选研究

Comparison and Selection of Anchor Excavation Schemes for Shallow Tunnel in Soft Rock

为了研究软岩地质条件下悬索桥隧道锚的合理开挖方案,以伍家岗长江大桥北岸隧道锚为研究对象,利用层次权重决策分析法结合FLAC3D软件,对三台阶法、三台阶临时仰拱法、正台阶环形开挖法和交叉中隔壁法等多种隧道开挖方案进行多维度对比分析.结果表明:层次权重决策分析法结论与数值计算结果一致,当目标指标着重于沉降变形和工程造价时,三台阶临时仰拱法为最优开挖方案.该结果同时说明,在隧道锚开挖方案选择上,将层次权重决策分析法和数值分析方法结合,能够为实际工程提供科学指导意见.

In order to study the reasonable excavation scheme of tunnel anchor of suspension bridge under soft rock geological conditions,taking the tunnel anchor of Wujiagang Yangtze River Bridge on the north bank as the research object,the hierarchical weight decision analysis method combined with FLAC3D software was used to make multidimensional comparative analysis of various tunnel excavation schemes such as three-step method,three-step temporary inverted arch method,positive step circular excavation method and cross middle partition method.The results show that the analytic hierarchy process(AHP)is consistent with the numerical results.When the target index focuses on settlement deformation and engineering cost,the three-step temporary inverted arch method is the best excavation scheme.In the selection of tunnel anchor excavation scheme,the combination of analytic hierarchy process(AHP)and numerical analysis can provide scientific guidance for practical projects.