基于LightGBM算法的供水管网抗震性能评估

SEISMIC PERFORMANCE EVALUATION OF WATER DISTRIBUTION NETWORK BASED ON LIGHTGBM ALGORITHM

  • 摘要: 为考虑管线地震破坏和震后修复的不确定性,多采用蒙特卡罗模拟(MCS)方法进行供水管网震后水力服务性能以及韧性评估。由于MCS产生的样本数量多,且每个样本进行水力模型计算耗时较长,导致采用MCS评估供水管网震后服务性能时存在计算量大、效率低的问题。该文采用LightGBM算法构建地震破坏供水管网服务性能的预测模型,代替每个MCS样本中水力分析模型,提升MCS模拟计算效率。代理模型的输入参数为管线水力重要度及其破坏点漏口面积,输出参数为管网中节点和管网整体的供水满足率。通过Benchmark案例管网验证了LightGBM代理模型的有效性;与水力功能分析模型计算结果相比,代理模型评估的管网震后服务性能相对误差为1.09%~1.88%,计算时间降低了73.1%~92.3%;对于管网震后恢复过程模拟和韧性评估问题,代理模型得到的不同恢复策略的韧性指标,与水力分析模型的结果相对误差小于1%。因此,基于LightGBM算法的代理模型可为城市供水管网震后性能评估、恢复过程模拟和韧性评估提供支撑。

     

    Abstract: In order to consider the uncertainty of seismic damages and post-earthquake restoration of water distribution pipelines, the Monte Carlo simulation (MCS) is generally used for seismic performance and resilience evaluation of water distribution network (WDN). Due to the large number of damage samples generated by MCS and the long time taken to perform hydraulic simulation of the WDN in each damage sample, the MCS approach usually accomplished with large computational burden. This study utilized the LightGBM algorithm to establish a surrogate model to predict the seismic performance of the WDN in each damage sample, instead of the hydraulic model-based analysis, aiming to improve the computational efficiency of seismic performance evaluation of WDN based on MCS. The inputs of the surrogate model are the hydraulic importance index and the earthquake-induced leakage area of the WDN pipelines, and the outputs of the surrogate model includes the water service satisfaction ratio of user nodes and the whole WDN. The effectiveness of the surrogate model based on LightGBM was verified through a benchmark WDN case, and the relative error of the seismic performance of the WDN evaluated by the surrogate model ranges from 1.09% to 1.88%, whereas the computational time was reduced by 73.1% to 92.3% compared with the traditional hydraulic model-based analysis. For the performance evaluation during the post-earthquake recovery process and resilience evaluation of the WDN, the resilience indexes evaluated by the surrogate model have a relative error of less than 1% compared with the results of the hydraulic analysis model. Therefore, the LightGBM-based surrogate model for the WDN performance evaluation provides an efficient tool for seismic performance evaluation, recovery simulation and resilience evaluation of the WDN.

     

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