考虑近断层脉冲型地震动影响的埋地管道地震易损性分析

SEISMIC VULNERABILITY ANALYSIS OF PIPELINECONSIDERING THE INFLUENCE OF NEAR-FAULTPULSE-TYPE GROUND MOTION

近断层脉冲型地震动具有短时高能量的脉冲特性,会对埋地管道等长周期结构造成较为严重的破坏。为研究近断层脉冲型地震动影响的埋地管道抗震性能,该文基于简化速度脉冲模型,结合脉冲周期、脉冲峰值的经验统计公式,模拟了不同地震动的方向性脉冲分量和滑冲脉冲分量,通过与ATC-63报告推荐的远场地震动中的高频成份进行叠加,合成了具有多种频率成分的近断层脉冲型地震动;在此基础上,进一步考虑空间变异性,生成了的空间相关多点非平稳地震动。利用ANSYS软件进行有限元建模,输入人工合成的地震动进行增量动力时程分析,建立了PGV与埋地管道最大应变之间关系的概率地震需求模型,结合管道极限破坏状态的划分,进而建立了考虑不确定性的不同管材、管径、壁厚及填覆土的埋地管道地震易损性模型。该模型为跨断层埋地管道地震风险评估中的地震易损性分析提供了理论基础。

The near-fault pulse-type ground motion has short-time and high-energy pulse characteristics,which will cause serious damage to long-period structures such as buried pipelines.In order to study the seismic performance of buried pipeline affected by near-fault pulse-type ground motion,the directional pulse component and slip impulse component of different ground motions are simulated by the grounds of a simplified velocity pulse model,combined with the empirical statistical formula of pulse period and pulse peak.The near-fault pulsetype ground motions with multiple frequency components are synthesized by superposing with the high-frequency component of far-field earthquake motion in the ATC-63.On this basis,considering the spatial variability,the spatially related multi-point nonstationary ground motions are generated.The finite element modeling is carried out by using ANSYS software,and the artificial ground motion is input for incremental dynamic analysis.The probabilistic seismic demand model,combined with the division of pipeline ultimate failure state,of the relationship between PGV and the maximum strain of buried pipeline is established,and then the seismic vulnerability model is established for the buried pipeline with different pipe materials,pipe diameters,wall thickness and filled soil considering uncertainty.The model provides a theoretical basis for seismic vulnerability analysis in seismic risk assessment of buried pipelines across faults.