上海地区盾构隧道结构安全评估方法研究

Research on Structural Safety Assessment for Shield Tunnel in Shanghai

基于上海软土地区盾构隧道运营期的受力特性,分析影响隧道结构安全的变形及病害指标,综合考虑指标的现场获取便利性,确定纵向变形、横向变形、渗漏水及表观损伤四项作为隧道结构安全评估的关键指标,并根据隧道使用功能和结构安全确定指标阈值划分;结合隧道穿越土层特性,确定各项指标权重;借助属性识别综合评判方法,对运营隧道结构安全进行快速评估;克服现有方法指标过多不宜获取的不足,使得安全评估的时效性和针对性更强。应用于上海轨道交通某重点监护区间,客观反映了周边基坑开挖对隧道安全状态的影响,可为维护保障提供指导。

Based on mechanical characteristic of shield tunnel during operation in Shanghai soft soil area,the deformation and disease indicators,which will affect the structural safety,are analyzed.Then the vertical and horizontal deformation,seepage,and apparent damage are selected as the key indicators.According to the function requirement and structural safety,the index threshold is determined.The attribute recognition method,combined with indicators weight related to the soil characteristics,is applied to the structural safety assessment of shield tunnel,which is more effective and targeted,and the applied indicators are easy to achieve.The method is applied to Shanghai metro intensive monitoring project.The result reflects the influence of the adjacent excavation pit and provides guidance to tunnel maintenance management.