脉冲型地震动下埋地管道易损性及巨震风险分析

Fragility and very rare earthquake risk of buried pipeline based on pulse-like ground motions

  • 摘要: 第五代《中国地震动参数区划图》(GB 18306—2015)第一次引入了极罕遇地震(巨震)作用,然而现行抗震设计规范仍然采用三水准设防原则,考虑巨震的抗震设计已成为结构抗震设计亟需解决的问题之一。本文基于连续小波变换的识别方法,选取2023年2月6日土耳其巨震中实测的12条脉冲型地震动以及12条无脉冲地震动,在此基础上对连续管道以及球墨铸铁管道开展增量动力分析(IDA),评估其易损性,最后将易损性分析结果与经验统计法得到的失效概率进行对比。结果表明:对于不同形式的埋地管道,脉冲型地震动的作用均会显著增加结构发生严重破坏的概率;相较于连续管道,球墨铸铁管道在地震动作用下更易发生破坏,且对脉冲型地震动更加敏感;基于实际震害数据的经验统计结果略小于无脉冲地震动作用下管道的破坏概率,但会显著低估脉冲地震作用下埋地管道的破坏。本文给出了不同类型埋地管道在脉冲型地震动作用下的失效概率,研究结果可为埋地管道在巨震以及脉冲型地震动下的风险评估以及抗震设计提供有力的理论依据。

     

    Abstract: The fifth generation “seismic ground motion parameters zonation map of China” (GB 18306―2015), which was promulgated and implemented in China, introduced the vary rare earthquake effect for the first time. However, the current seismic design specifications still adopt the three-level defense principle. The seismic design for vary rare earthquake has become one of the urgent issues that need to be addressed in structural seismic design. Based on the identification method of continuous wavelet transform, this paper selects 12 pulse-like ground motions and 12 non-pulse seismic motions recorded in the Turkey mega earthquake on February 6, 2023. The incremental dynamic analysis (IDA) is conducted on continuous pipelines and ductile iron pipelines to evaluate their seismic fragility. The fragility analysis results are compared with the failure probability obtained by empirical statistical method. The results show that the effect of pulse-like ground motions significantly increases the probability of serious structural damage for buried pipelines with different forms. Compared with continuous pipelines, ductile iron pipelines are more prone to damage underground motions, and are more sensitive to the pulse-like ground motion. The empirical statistical results based on actual seismic damage data are slightly lower than the failure probability of pipelines under non-pulse earthquake motion, but significantly underestimate the damage of buried pipelines under pulse earthquake motion. In this paper, the failure probability of different types of buried pipelines under pulse-like seismic motions is given, and the research results can provide a strong theoretical basis for the risk assessment and seismic design of buried pipelines under very rare and pulse-like ground motions.

     

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