大型桥梁施工风险动态评估

Dynamic Risk Assessment of Large Bridge Construction

摘要:

针对大型桥梁施工风险动态评估问题，采用结构?风险分解识别法完成风险元初步识别，引入决策与实验室方法识别动态评估风险元并构建风险元传递网，最后结合贝叶斯网络及GeNIe软件对风险元传递网进行贝叶斯概率计算，并结合逆向推理和敏感性分析获得关键风险元及主要风险链。采用该方法开展五峰山长江大桥施工全过程风险动态评估。结果表明，全桥评估中共识别出234个动态评估风险元，辨析出104个关键风险元及相关主要风险链。计算出施工前及主梁完成后“高速铁路行车安全”风险概率值分别为0.065 2、0.009 1，对应的关键风险元为沉井不均匀沉降、主缆线形偏差等，主要风险链为：沉井不均匀沉降→锚体变位→锚固系统变位→主缆线形偏差→吊索不均匀变形→主梁线形变化→铁路桥面平顺性不足→高速铁路行车安全。

Abstract:

To solve the problem of dynamic changes in risk assessment of large-scale bridge engineering， the structure-risk decomposition identification method was used to complete the preliminary identification of risk elements. Beside the DEMATEL was introduced to identify dynamic assessment risk elements， and the risk element transmission network was extracted. Moreover， Bayesian network and Genie software were applicated together with the reverse reasoning and sensitivity analysis to perform Bayesian probability calculation on the risk element transfer network， for obtaining the main risk element transfer chain and the key risk elements. This method was used to conduct the dynamic risk assessment of the whole construction process of the Wufengshan Yangtze River Bridge. The results show that 234 dynamic risk elements， 104 key risk elements and the corresponding main risk chains were identified in the whole bridge construction. The probability values of “high-speed railway driving safety”before construction and after the completion of the main girder were found to be 0.065 2 and 0.009 1 respectively. The related key risk elements are uneven settlement of caisson， linear deviation of main cable and so on. The main risk chain is uneven settlement of caisson →position change of anchor body → displacement of anchoring system → deviation of main cable line shape → uneven deformation of sling → line shape change of main girder → insufficient smoothness of railway bridge surface → driving safety of high-speed railway.