基于模糊事故树的深基坑防排水风险评估

Risk Assessment Based on Fuzzy Fault Tree for Waterproof and Drainage System in Deep Excavation

降水是影响基坑工程施工安全的关键性因素之一,为了减少和预防基坑防、降水不当导致的基坑失稳事故,建立了基于模糊事故树法的基坑防排水工程风险评估体系。从止水、排水、降水三个方面,对基坑工程防排水措施中的危险源进行了分析和辨识,建立了基坑防排水事故树。用三角模糊数表述基本事件发生概率,计算得到系统模糊失效概率。通过中值法进行重要度分析,得到系统各基本事件的模糊重要度。工程实例应用表明,评估结果与实际情况较为符合,系统模糊失效概率能较好的反映基坑防排水系统的风险水平,模糊重要度的分析可为制定基坑施工安全措施和应急方案提供指导。

Water was a key factor which influenced the safety of civil engineering, to prevent and reduce waterproof and drainage accidents, the risk evaluation system of the waterproof and drainage system in excavation engineering based on Fuzzy Fault Tree Method was established in this work. Waterproof and drainage and its influencing factors in excavation engineering were studied, and the fault tree of waterproof and drainage was set up from three aspects, which were sealing, draining, dewatering. To deduce the defect that the probabilities of uncertain events were presented as exact values in conventional fault tree analysis, the probabilities of events were described by the triangular fuzzy number to calculate the fuzzy failure probability of the top event. Fuzzy importance analysis of basic events was achieved by median method. At last, a project case was assessed by the system, and the result of the assessment accorded closely with the status of the project. The fuzzy failure probability of the top event can reflect the risk level of system appropriately, and the result of basic events＇ fuzzy importance degrees can be used to make safety measures of the engineering.