高土石坝的地震动力响应分析方法研究与应用

Study on method for analysis on seismic dynamic response of high earth-rockfill dam and application

基于现有的土石料动力本构关系,综合分析了土石料非线性弹性模型和动弹塑性模型的优缺点,以及对高土石坝动力响应分析的适用性。应用等效线性粘弹性本构模型建立动力方程,根据总应力法进行地震反应分析,基于动力反应结果利用Newmark法或等效应变势法进行永久变形分析,依据不排水动力试验结果进行关键曲线的液化判断是最为合适的高效高土石坝地震动力响应计算途径。利用该途径,依据糯扎渡水电站高土石坝坝料特性,对该坝的动力响应进行了人工合成地震波下的动力响应分析,得出该坝的加速度放大系数都小于2,但是"鞭梢"效应明显,坝顶加速度反应较大,可在坝顶附近采取局部抗震加固措施,该情况与坝体抗震结构设计一致。

Based on the existing earth-rock dynamic constitutive relationship,the merits and defects of both the earth-rock nonlinear elastic model and the dynamic elastic-plastic model as well as their applicabilities are comprehensively analyzed herein. It is a most appropriate way to calculate the seismic dynamic response of high earth-rockfill dam with high efficiency that the equivalent linear viscoelastic constitutive model is applied to establish the dynamic equation,the seismic response is analyzed with the total stress method,the permanent deformation is analyzed with Newmark method or equivalent strain potential method base on the result of the dynamic response and the liquefactions of the key curves are judged with the result of the undrained dynamic test.With this way,the dynamic response of the high earth-rockfill dam for Nuozhadu Hydropower Station under the effect of the artificial seismic wave is analyzed in accordance with the construction materials for it. It is obtained that all the acceleration amplification coefficients of the dam are less than 2,however,the whiplash effect is obvious and the acceleration response at the dam crest is relatively larger,thus the seismic reinforcement measures can be adopted near the dam crest,which accords with the seismic design for the structure of the dam body.