深覆盖软土场地弹塑性反应谱分析

Analysis on Inelastic Response Spectra of Site with Deep and Soft Soil

基于汶川地震中不同震中距处获得的实测基岩地震动,以不同震中距来考虑不同的设计地震分组,通过典型深覆盖软土场地地震反应分析得到地表加速度响应,以弥补目前深覆盖软土场地实测地震动记录的不足。对得到的地表加速度响应的弹塑性反应谱进行了分析和拟合。分析表明,在等位移准则或等延性系数下,设计地震分组对深覆盖软土场地弹塑性反应谱的折减系数和衰减规律影响显著,完善了目前弹塑性反应谱研究时未考虑设计地震分组的不足。同时,通过相应的物理边界条件和数学条件,提出基于设计地震分组的深覆盖软土场地弹塑性反应谱拟合函数,得到了可供工程应用的弹塑性设计反应谱。

Based on the measured bedrock earthquake motions at different epicenter distances in Wenchuan earthquake, and different earthquake classifi- cations are considered in accordance with different epicenter distances. Through the seismic response of the typical site with deep and soft soil, the sur- face acceleration response is obtained, so as to perfect the measured earthquake motion records of site with deep and soft soil. The inelastic response spectra of the surface acceleration response obtained is analyzed and fitted. The analysis show-s that with the equal displacement rule and the equal ductil- ity factor the designed earthquake classification has patent impact on the reduction factor and decaying rule of the inelastic response spectra of site with deep and soft soil, perfecting the deficiency. Through corresponding physical boundary conditions and mathematical conditions, the fitting function for inelastic response spectra of site with deep and soft soil based on designed earthquake classification is proposed, and the inelastic design response spec- trum available for engineering application is obtained.