基于MCMC-CCRAA的大跨径斜拉桥施工风险预警模型

发布时间：2018-10-14 17:05

【摘要】：为预防桥梁施工过程中安全事故的发生,完善施工风险预警机制,提升施工风险评估的可靠性,结合大跨径斜拉桥施工风险特点,提出了基于MCMC法与CCRAA法的大跨径斜拉桥施工风险预警模型。依据施工工序,对大跨径斜拉桥施工过程进行风险源识别,建立了施工风险层次评价体系。由于大跨径斜拉桥施工风险分析的信息较少,为最大限度地利用已有信息,采用MCMC方法中的Gibbs抽样,通过数值模拟直接从后验分布中生成参数向量的仿真样本,并针对这些仿真样本进行了统计推断,求解了复杂后验分布高维积分,进而得到了一级风险源的施工风险概率。运用CCRAA法首先确定风险基值,计算了相对海明距离,按比例对各一级风险源的风险值进行了补偿,得到风险区间后再进行风险聚合,求得二级风险源的施工风险概率,避免了聚合风险出现极值或者对风险概率产生依赖。基于以上两种方法,并结合大跨径斜拉桥施工实际,构建了施工风险概率区间,进而建立了大跨径斜拉桥施工风险预警模型,并实施了施工风险二次评估,以确保桥梁施工安全。通过工程实例分析表明:该预警模型对大跨径斜拉桥实际施工风险能做到有效评估,对于保证桥梁施工安全具有一定的实用价值。
[Abstract]:In order to prevent the occurrence of safety accidents during the construction of bridges, to perfect the early-warning mechanism of construction risks, to enhance the reliability of construction risk assessment, and to combine the characteristics of construction risks of long-span cable-stayed bridges, Based on MCMC method and CCRAA method, the construction risk early warning model of long span cable-stayed bridge is proposed. According to the construction procedure, the risk source of the long span cable-stayed bridge is identified, and the risk hierarchy evaluation system is established. Because the information of construction risk analysis of long-span cable-stayed bridge is less, in order to make the best use of the existing information, the Gibbs sampling in MCMC method is used to generate the simulation sample of parameter vector directly from the posterior distribution by numerical simulation. Based on the statistical inference of these simulation samples, the complex posterior distribution high dimensional integral is solved, and the construction risk probability of the primary risk source is obtained. By using CCRAA method, the risk base value is first determined, the relative hamming distance is calculated, the risk value of each primary risk source is compensated in proportion, the risk interval is obtained and then the risk aggregation is carried out, and the construction risk probability of the secondary risk source is obtained. Avoid aggregation risk extreme value or risk probability dependence. Based on the above two methods and combined with the construction practice of the long-span cable-stayed bridge, the construction risk probability interval is constructed, and the construction risk early-warning model of the long-span cable-stayed bridge is established, and the construction risk is evaluated twice. To ensure the safety of bridge construction. The analysis of engineering examples shows that the early warning model can effectively evaluate the actual construction risk of long-span cable-stayed bridge and has certain practical value to ensure the safety of bridge construction.
【作者单位】：西安公路研究院;
【基金】：陕西省交通科技项目(13-17k)
【分类号】：U445

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