基于SOILQUAKE软件方法的厚层淤泥场地设防地震动参数确定探讨

Determination of ground motion parameters for the thick silt site based on SOILQUAKE software method

以天津滨海某厚层淤泥场地为例,分别采用等效线性化法(LSSRLI-1)和新一代土层地震反应分析SOILQUAKE软件方法在场地危险性计算确定的不同设防水准地震动输入条件下进行了建模土层地震反应计算。计算结果表明:(1)对厚层淤泥软弱场地,与新版区划图结果相比等效线性化法可能会低估场地地震作用,甚至是低估场地设防烈度;(2)SOILQUAKE软件方法在软弱场地设计地震动参数确定时仍能体现一定的放大作用,尤其是强地震动作用下,克服了等效线性化方法在软弱场地计算时出现的设计谱明显矮、宽现象,与当前认识相一致,为软弱场地重大工程设防参数确定提供了参考;(3)SOILQUAKE软件方法在软弱场地设计地震动参数确定较新版区划图结果设防标准有大幅度提高,考虑到相关抗震设防规范的协调性,还需进一步对其他类型软弱场地进行大量强震记录输入计算检验,以便更好的工程应用。

Taking a thick silt site in Binhai District of Tianjin as an example,the equivalent linearization method(LSSRLI-1)and the analysis method of soil earthquake response(SOILQUAKE)were used to calculate the earthquake response of soil layers under seismic ground motions of different fortified levels.The results showed that:(1)Compared with the results of the new zonation map,the equivalent linearization method may underestimate the seismic action of the thick silt soft site,or even underestimate the fortification intensity of the site;(2)The method of software SOILQUAKE can still show a certain amplification effect in determining the design seismic parameters of soft site,especially under strong earthquakes,it overcomes the phenomenon that the design spectrum is obviously low and wide in the calculation of soft site,which can provide a reference for the determination of fortification parameters of major projects in soft site;(3)The design ground motion parameters of soft site determined by the method of software SOILQUAKE are greatly superior to the results of the new zonation map.Considering the coordination with relevant seismic fortification codes,a large number of strong earthquake records need to be further input,calculated and verified for other types of soft sites,so as to be better applied to actual projects.