基于物元理论和证据理论的盾构隧道施工邻近建筑物风险评价

随着城市地铁建设规模的扩大,隧道施工对邻近建筑物基础土体的沉降变形有很大的影响,为实现对隧道施工邻近建筑物的安全风险评价,基于大量工程实践,从隧道工程条件、土质条件、建筑物自身条件、施工方法及管理水平四方面提出了涵盖19个因素的评价指标体系,并将其划分为五个等级,提出一套基于物元理论和证据理论的安全评价方法,以物元理论计算关联度作为基本可信度分配,再基于证据理论进行融合得到最终安全状态,并基于蒙特卡洛原理确定敏感性因素。以武汉轨道交通2号线隧道邻近的6栋建筑物为例,对其进行安全风险评价和敏感因素确定,得出1栋建筑物状态较危险,1栋建筑物状态较安全,4栋建筑物状态安全的结论,并通过敏感性分析得出覆跨比、地层损失、泊松比、上部完损情况和管理水平对该区域建筑物的影响较为敏感,这为有针对性地提出改进措施提供了依据。

Risk Assessment of Adjacent Buildings Induced by Shield Tunneling Construction Based on Matter-element Theory and Extension Theory

In order to realize the safety evaluation of adjacent buildings during metro tunneling construction, the paper carries out the risk mechanism analysis of adjacent buildings, and proposes a indicator system including 19 indexes from four aspects: tunneling conditions, soil conditions, building conditions, and construction method and management level. The indexes are divided into five levels. A method based on extension theory and D-S evidence theory is proposed to calculate the correlation degree with extension theory and fuse with D-S evidence theory to get the final safety condition. And sensitive factors can be obtained through Metro-Carlo method. At last, six adjacent buildings of tunneling construction in Wuhan line 2 are set as an example to evaluate the safety level and get the sensitive factors. The results show that one building is risky, one is safer, and rest are safe. Through sensitivity analysis, it is found that the span ratio, formation loss, Poisson’s ratio, upper damage and management level are sensitive to the impact of buildings in the area, which provides a basis for targeted improvement measures.