基于WBS-RBS的超大型沉井基础施工风险评估

Assessment of Construction Risk for Super-large Open Caisson Foundation Based on WBS-RBS

面积庞大的沉井结构、复杂的地基土特性等因素导致大型桥梁沉井基础在施工过程中风险突出。依托五峰山长江特大桥北锚碇沉井基础开展施工风险评估研究:首先,基于工作与风险结构分解(Work Breakdown Structure-Risk Breakdown Structure,WBS-RBS)的方法对沉井基础施工全过程进行底层工序与风险源的二维分解,初步识别风险源,再引入专家调查意见对风险源增补调整;然后,基于专家调查法按类别完成风险发生概率和损失程度评估;最后评出风险等级。结果表明:沉井基础施工过程风险影响因素较多,识别出的风险源共97项,包括沉井开裂、翻砂涌水等8项重大风险源;对风险源提出了针对性控制对策,为沉井基础施工提供有效的风险控制依据。

Large area of open caisson structure,complex foundation soil characteristics and other factors lead to therisk of large bridge open caisson foundation in the construction process.Based on the open caisson foundation of thenorth anchorage of Wufengshan Yangtze River Bridge,the construction risk assessment study was carried out.Firstly,based on the work breakdown structure-risk breakdown structure(WBS-RBS)method,the two-dimensional riskdecomposition of the underlying work package and risk sources was carried out for the whole process of open caissonfoundation construction,the risk sources were preliminarily determined by coupling the results,and the expert surveyopinions were introduced to modify and supplement the risk sources.Then,based on the expert survey method,the riskoccurrence probability and the risk loss degree were evaluated according to the category.Finally,the risk level wasevaluated.The results show that there are many risk factors in the construction process of open caisson foundation,and97 risk sources are identified,including 8 major risk sources,such as open caisson cracking,sand boiling and watergushing.The corresponding control countermeasures are put forward to provide effective risk control basis for opencaisson foundation construction.