摘要
竖向地震动对长、大工程结构具有重要影响,在2017年召开的16WCEE上,出现了多篇涉及竖向地震动衰减关系、工程特征、数值模拟等方面的研究。本文聚焦于竖向地震动衰减关系,在总结其研究新进展基础上,探讨了目前最新的NGA-West2竖向模型对我国四川地区地震动的预测能力。基于四川地区中强震的距离200 km以内的竖向强震记录,比较了模型预测值与观测值的差异,通过残差分析方法研究了事件间残差、事件内残差的分布特征。结果表明:总体而言,NGA-West2模型高估了四川地区长周期加速度反应谱,而预测短周期加速度反应谱的误差相对较小;NGA-West2模型的震级项、场地项与四川地区实际观测数据表现出的规律存在差别,距离项与实际地震动随距离的衰减规律较为吻合。因此,直接利用NGA-West2模型预测四川地区竖向地震动存在一定局限性,需要根据实际观测数据对震级项和场地项进一步修订。
Vertical ground motion is a significant factor affecting the large-span or large-scale engineering structures. There are some papers involved in the attenuation relationship, engineering features, numerical simulation and other aspects for vertical ground motion in the proceeding of the 16WCEE in 2017. This paper focuses on the attenuation relationship for vertical ground motion and summarizes its new progress to discuss the prediction applicability of latest NGA-West2 models to ground motion in Sichuan region. By using vertical strong motion recordings within rupture distance less than 200 km from moderate to strong earthquake in Sichuan region, we compare the results predicted by NGA-West2 models and observed values. Then the distribution characteristics of inter-event and intra-event residuals is studied through residuals analysis method. Results indicate that the NGA-West2 models sig- nificantly overestimate the long period vertical spectra acceleration, and the prediction error of short period vertical spectra acceleration is relatively smaller. The magnitude scaling and site effect term of NGA-West2 models differ significantly from the result of ground motion observation. The distance scaling can relatively well reflect the attenuation tendency of the observed ground motion with distance. Therefore using NGA-West2 models to predict vertical ground motion in Sichuan region is improper. Appropriate correction on magnitude scaling and site effect term through observed regional ground motion should be made before getting more reliable prediction by NGA-West2 models.
出处
《地震工程与工程振动》
CSCD
北大核心
2017年第3期67-79,共13页
Earthquake Engineering and Engineering Dynamics
基金
国家自然科学基金项目(51578516
51238012)
中国地震局工程力学研究所基本科研业务费专项资助项目(2016A01
2016A04)~~
