基于DFTA-BIM的大型桥梁沉井施工风险评估

彭耀

摘 要

我国大型桥梁工程建设近年来不断取得迅猛发展，而沉井基础由于在结构稳定性等方面的诸多优势，目前已成为大型桥梁工程中最常见的基础类型之一。随着大型桥梁工程建设环境的不断复杂化，沉井施工的潜在风险也不断攀升。因此，为了减少沉井施工可能带来的人员伤亡及经济损失，有必要开展和加强大型桥梁沉井施工风险评估研究工作。本文针对上述问题，结合动态故障树分析法（DFTA）、BIM、模糊数学、离散贝叶斯等相关理论，对大型桥梁沉井施工风险评估展开了系统的分析与研究。主要内容如下：

（1）通过总结沉井基础的常见类型、施工流程及主要施工工艺，重点分析沉井施工的关键阶段——沉井下沉阶段，归纳出沉井下沉施工过程中的常见风险事故及其原因。

（2）针对沉井施工的复杂性以及传统风险评估方法在动态评估方面的不足，本文结合动态故障树分析法（DFTA）在定量分析及BIM在数据集成与可视化等方面的优势，提出基于DFTA-BIM的沉井施工风险评估模型，并阐述模型的总体框架及应用流程，实现对沉井施工的动态、可视化风险评估。

（3）以武汉某大桥沉井为例，运用DFTA-BIM模型重点研究沉井下沉阶段的风险。首先，构建沉井结构、地质等BIM模型，并通过风险识别构建DFTA模型；其次，应用模糊数学与离散贝叶斯对模型进行计算与分析；最后，进行风险可视化表达与应对。

本文通过工程实例研究，验证DFTA-BIM沉井施工风险评估模型的实用性与优势，为建设工程施工风险评估的进一步发展提供参考。

关键词：沉井施工 风险评估 动态故障树 BIM 离散贝叶斯

Abstract

The large bridge construction in China has been developing rapidly in recent years, and the foundation of the caisson has become one of the most common structure foundation types in the large bridge project because of its advantages in structural stability and so on. With the continuous complication of large-scale bridge construction environment, the potential risk of the caisson construction is also rising. Therefore, in order to reduce the possible casualties and economic losses in the construction of the caisson, it is necessary to carry out and strengthen the research on the risk assessment of the large bridge caisson construction. In this dissertation, the risk assessment of large bridge caisson construction was analyzed and studied based on the theory of dynamic fault tree analysis (DFTA), BIM, fuzzy mathematics, discrete Bayes and other related theories. The main contents are as follows:

（1）By summarizing the common types of the caisson foundation, the construction process and the main construction technology, this dissertation has focused on the key stage of the caisson construction—the sinking stage of the caisson, and the common risk accidents and the causes in the sinking of the caisson sinking has been summarized.

（2）In view of the complexity of the caisson construction and the shortage of the traditional risk assessment method in the dynamic evaluation, based on the advantages of the dynamic fault tree analysis (DFTA) in quantitative analysis and the advantages of BIM in data integration and visualization, the risk assessment model of the caisson construction—DFTA-BIM was put forward in the dissertation, and the overall frame of the model was also expounded. Through this model, the dynamic and visual risk assessment of the caisson construction has been realized.

（3）By taking a caisson of a bridge in Wuhan as an example, the risk of caisson sinking stage was mainly studied by using DFTA-BIM model. First, the BIM model of the caisson structure and geology was constructed, and the DFTA model was constructed through risk identification. Secondly, the fuzzy mathematics and discrete Bayes were used to calculate and analyze the model. Finally, the visual expression and response of the risk were carried out.

Through the engineering case studies, the practicality and advantages of the DFTA-BIM caisson construction risk assessment model has been validated in the dissertation, and can be referred to the further development of the construction project risk assessment.

Key words: caisson construction; risk assessment; dynamic fault tree; BIM; discrete Bayes