结合历史大震的反演探讨砖石古塔的抗震变形能力

通过对1604年泉州海外721级大震进行反演,得到该次地震在泉州东、西塔塔址的基岩水平峰值加速度和基岩水平加速度反应谱;然后,结合试验测定的场地岩土力学性能,采用一维等效线性化波动法计算土层地震动反应,得到塔址地表水平加速度时程;接着,基于MATLAB平台,结合地震危险性分析结果,采用Wilson-θ法自编程序,对东、西塔进行结构弹性时程动力分析,并根据史料记载的东西塔在这次地震中的破坏状况,得到东、西塔的弹性层间位移角限值。与相关文献的结果相比,两者数值上相差不大,但本文的分析方法更符合当前的认知水平。本文结果可供古石塔抗震变形验算和震害预测参考。

Investigation of Aseismic Deformability of Ancient Masonry Pagoda Based on the Inversion of Historical Megaseisms

The inversion of Megaseism M 712 in coastal area of Quanzhou in 1604 is performed by means of deterministic parsing of seismic hazards,to attain the matrix horizontal peak acceleration (191gal) as well as the response spectrum of matrix horizontal acceleration at the pagoda site caused by the earthquake. Then combined with the site geotechnical characteristic determined in the test,one-dimensional equivalent linearized fluctuation is applied to calculate the earthquake responses of the soil layer in order to attain the horizontal acceleration time-history in the site ground. Based on the MATLAB platform together with the findings of seismic hazard analysis,the program Wilson θ-method is used to conduct the elastic time-history dynamic analysis of structures of East and West Towers. According to the destruction conditions of East and West Towers in the earthquake from historic records,the limited value 1/532 of the elastic interlayer displacement in East and West Towers is obtained. There is no great difference between the analytical results in this paper and those of Reference 4,but the former seems to be more theoretical reasonable. This analysis can be used as a reference for investigation of the aseismic deformability of ancient masonry pagodas and prediction of seismic damages.