液化与非液化场地加速度反应谱对比

发布时间：2018-05-10 10:53

本文选题：新西兰地震 + 液化　；参考：《岩土力学》2014年S1期

【摘要】：通过对2011年新西兰发生的6.3级地震中获取的硬土场地、软土场地和液化场地强震记录实测资料进行分析,研究包括3种类型场地的地震动特征及其相互关系。分析的强震记录为震中距小于50 km,且峰值大于0.05g的23个场地上的加速度记录,其中含3个硬场地、11个软场地和9个液化场地。3种类型场地上的放大系数谱对比分析表明,硬土场地、软土场地和液化场地上的地震动特征具有明显区别,三者层次清晰,差别显著,从地震动表现上液化场地已构成一个与常规场地并列的独立单元;液化场地减少地震动高频分量但同时对低频分量显著放大,与非液化场地相比,液化场地可使其上短周期结构反应减小一半,但同时可使其上长周期结构反应放大2.5~5.0倍;土层的液化对此次地震中克莱斯特彻奇市中心CTV大楼的破坏应有很大影响,大楼自振周期约为0.7 s,地震中土层液化使场地加速度反应谱卓越周期由0.1~0.3 s增到0.5~1.0 s,与大楼的自振周期趋于吻合,加重了大楼震害。以此为鉴,按现有规范中地震动的设计方法,如遇液化场地将对长周期结构给出明显危险的结果,因此从振动角度今后进行结构抗震设计时,可液化场地上的地震动应给予特殊考虑。
[Abstract]:Based on the analysis of the measured data of hard soil site, soft soil site and liquefaction site recorded during the earthquake of M = 6.3 in New Zealand in 2011, the research includes three types of ground motion characteristics and their relationships. The strong earthquake records are the acceleration records of 23 sites whose epicentral distance is less than 50 km and the peak value is more than 0.05g, including 3 hard sites, 11 soft sites and 9 liquefaction sites. The characteristics of ground motion in hard soil site, soft soil site and liquefaction site are obviously different, the three layers are clear and the difference is significant. The liquefaction site has formed an independent unit juxtaposed with the conventional site in terms of ground motion. The liquefaction site can reduce the high frequency component of ground motion but amplify the low frequency component obviously. Compared with the non-liquefaction site, the liquefaction site can reduce the structural response of the upper short period by half, but at the same time, it can enlarge the response of the upper long period structure by 2.5 or 5.0 times. The liquefaction of the soil layer should have a great impact on the destruction of the CTV building in downtown Christchurch during the earthquake. The natural vibration period of the building is about 0.7 s, and the soil liquefaction in the earthquake increases the outstanding period of the ground acceleration response spectrum from 0.1 ~ 0.3 s to 0.5 ~ 1.0 s, which tends to coincide with the natural vibration period of the building, thus exacerbating the earthquake damage of the building. In view of this, according to the design method of ground motion in the existing code, if the liquefaction site is encountered, it will give obvious dangerous results to the long-period structure, so in the future seismic design of the structure from the vibration point of view, Special consideration should be given to ground motion on liquefiable sites.
【作者单位】：中国地震局工程力学研究所地震工程与工程振动重点实验室;
【基金】：国家自然科学基金资助(No.51278472,No.41272357)
【分类号】：TU435

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