基于CCRAA熵值模型的双向顶推钢混组合梁风险评估

Risk Assessment of Steel-concrete Composite Beam by Bidirectional Incremental Launching Method Based on CCRAA Entropy Model

为保障桥梁施工的安全可靠性,预防施工过程中事故的发生,结合大悬臂双向顶推钢混组合梁桥施工风险因素的不确定性特点,提出了一种基于CCRAA熵值模型的风险评估方法。依据双向顶推钢混组合梁的施工工序及专家宝贵经验,综合考虑多维不确定风险因素,对项目整体进行了全面风险源辨识,并建立了风险层次分析模型。运用引入修正系数的LEC法确定了各风险指标值,并对风险特征值进行了最优化处理。由于各风险因素之间的综合影响对风险指标权重值具有一定依赖性,基于风险源辨识结果及风险指标值的确定,构建了CCRAA熵值模糊评判模型。首先运用熵权理论确定了多指标风险因素权重值,根据风险因素集在风险全集中的离散型,确定了风险补偿基值。再利用CCRAA算法按比例对各特征权重值进行了分配补偿,保证风险指标权重值收敛于聚类中心,融合各风险因素之间的互相干扰。最后,运用经典的兼具定性与定量特点的模糊综合评判矩阵理论对各风险源及项目整体进行了风险等级判定。实例分析表明:采用CCRAA熵值模型的风险评估方法对大悬臂双向顶推钢混组合梁桥施工进行风险研究,不仅能做到有效评估,并且理论完备、技术可行,对后续具有相同施工工艺的桥梁进行风险评估具有借鉴意义。

In order to ensure the safety and reliability of bridge construction and prevent accidents during construction process, based on the uncertainty characteristics of the construction risk factors of large cantilever composite beam bridge by bidirectional incremental launching method, a risk assessment method based on CCRAA entropy model is proposed. According to the construction process and expert experience of this composite beam, comprehensively considering the multi-dimensional uncertain risk factors, the overall risk sources of the project are identified and the risk level analysis model is established. Each risk indicator value is determined by using LEC method with correction coefficient, and the risk characteristic values are optimized. Since the comprehensive influence of various risk factors has a certain dependence on the weights of risk indicators, based on the identification result of risk sources and the determination of risk indicator values, a fuzzy evaluation model of CCRAA entropy value is constructed. First, the weights of multi-indicator risk factors are determined by using the entropy weight theory, and the risk compensation base value is determined according to the discrete type of risk factor set in the total risk set. Then, each characteristic weight is allocated and compensated by using CCRAA algorithm according proportion to ensure that the risk indicator weight converges to the cluster center and integrates the mutual interference among various risk factors. Finally, the risk levels of each risk source and the whole project are judged by using the classical fuzzy comprehensive evaluation matrix theory with qualitative and quantitative characteristics. The example analysis shows that the risk assessment method based on CCRAA entropy model to study the construction risk of subject bridge not only can it be effectively evaluated, but also the theory is complete and technically feasible, which is of reference significance for subsequent risk assessment of the bridges with the same construction technology.