建築基礎開挖崩坍事故之分析

Analysis of Collapse Accident of Excavation Construction of Building Foundation

近年來國內營建工程安全事故發生頻傳，其不僅危及施工人員與公共的安全，且對工期的延宕、成本的增加及承包商之信譽，均具嚴重的不良影響。失誤樹分析(FTA)是一種廣為工業界認同可有效地分析事故之因果關係與發生機率的技術。然而，由於事故發生的歷史資料缺乏，以及事故發生的肇因中，例如人為錯誤，多具含糊性，因此難以準確地估計出事件的發生機率，此為失誤樹在應用上最主要的限制；而模糊集(FS)為處理此類問題的良好方法。此外，基於層級分析法(AHP)為常用以分析因子間相對重要度（頻率）之方法，故本文提出一結合FTA、FS及AHP之分析模式，用以評估擋土開挖事故的失誤率。為驗證模式的有效性與實用性，本文以高雄市建築物擋土開挖發生崩坍的事故為案例進行探討。結果驗證了本模式可作為一種新的安全評估技術，用以協助安全管理人員有效地分析擋土崩坍事故之發生。

Numerous accidents related to excavation of building foundations occurred during recent years, which not only endangered the construction worker and the public, but also had severe adverse impacts on project delay, cost overrun and contractor’s reputation. Fault Tree Analysis (FTA), a widely recognized technique for industry safety, can effectively evaluate cause-and-effect relationship and accident probability. However, the major restriction for using FTA is that it’s difficult to accurately assess accident probability when historical data are insufficient and factors such as human error are vague in nature. On the other hand, Fuzzy Sets (FS) can be used to cope with this problem. In addition, because Analytic Hierarchy Process (AHP) is a commonly used approach to analyze relative importance (frequency) of each paired factor, this paper proposes an analytical model integrated with FTA, FS and AHP to assess the probability of collapse accident of excavation construction. A case study of the building excavation in Kaohsiung city is performed to demonstrate the effectiveness and practicality of this model. The results show that this model can be a new technique that assists safety managers to effectively assess collapse accident during excavation construction.