厚软覆盖层场地地震反应分析方法研究

遭遇地震动作用时,厚软覆盖层场地由于其剪切模量低,极易产生较大的剪应变,采用等效线性化方法进行土层反应分析计算得到的响应高频成分被低估,峰值加速度偏低,对于工程抗震设防偏于不安全。本文给出了基于移动平均线和Parzen谱窗的频率相关等效线性化方法,并和有实际强震记录的厚软场地进行了对比分析,结果表明本文方法比等效线性化方法能更有效地模拟地震波在厚软覆盖层场地中的传播规律。最后采用本文方法和等效线性化方法对天津滨海新区某一典型厚软场地进行了地震反应计算,并对计算结果进行了对比分析。

SEISMIC ANALYSIS OF DEEP SOFT DEPOSIT SITE

When subjected to earthquake motions, the deep soft soil easily undergoes large deform due to its low shear modulus. The equivalent linear method is traditionally used to perform site response. For deep soft deposit site, the high frequency composites and peak acceleration values of the site response are underestimated if the equivalent linear method is used. It is dangerous for the structure if the site response is used to perform anti-seismic design. The frequency-dependent equivalent linear method is proposed in this paper. It considers the moving average and Parzen spectrum window theory. Results of the two methods are compared with the observed earthquake motions. This comparison shows that the method proposed in this paper is more effective than the traditional method in simulating wave propagation in the deep soft site. Finally, the two methods are used to perform the site reponse for one engineering site located at Binhai New District. The results are analyzed.