浅埋大跨隧道穿越复杂建筑物安全风险分析及评估

SAFETY RISK ANALYSIS AND ASSESSMENT OF COMPLEX BUILDINGS IN SHALLOW-BURIED LARGE-SPAN TUNNEL CONSTRUCTION

城市隧道开挖引起的环境安全问题越来越受到人们的广泛关注,如何减小隧道暗挖施工对既有结构,尤其是既有地表建筑物的影响非常重要。与一般结构物不同,地表建筑物在结构上更具有复杂性和特殊性,对变形更敏感,破坏机制复杂,一旦发生破坏后果也更加严重。厦门机场路一期工程在浅埋、大跨及复杂地质工程条件下穿越地表密集建筑物群,建筑物的安全是决定隧道施工环境安全乃至工程顺利进行的关键。在简要分析隧道开挖对建筑物的影响机制及因素的基础上,依据本工程暗挖隧道穿越的63栋建筑物的查勘结果对其进行详细分类,而后引入模糊数学综合评判方法,总结了两大类9种主要作用因素,分别建立隶属函数并选取不同权重,对建筑物风险的不同程度用模糊语言进行评价,最终划分为5个等级,对工程施工具有一定的指导和借鉴意义。

Increasing attention to urban environment safety due to urban tunnel excavation is focused in recent years. Therefore,it is significant to minimize the impact of tunnel construction on existing structures,facilities and especially some buildings. Compared with other structures,buildings are more sensitive to external effects because of particularity and complexity of structure;and their deformation mechanisms are more complicated,thus the accident consequences are more serious correspondingly. The 1st-stage Xiamen Airdrome project passes through a large number of buildings with shallow-buried large-span tunnel in complex geology strata,making the buildings protection crucial to assure environment safety and successful tunneling. Consequently,the mechanism and factors of tunneling-induced influence on buildings should be analyzed first,and then,after foundation and structure type, height and current damage condition,etc.,are classified,the safety evaluation of all the 63 buildings is then performed. Fuzzy-synthetic evaluation method is introduced in risk assessment and rating here. Nine key affecting factors of two general kinds are selected and the member function and weight of these factors are also determined. It is predicted that anticipated safety target of these buildings of different risk levels could be achieved with this specific guiding meaning.