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ISSN 2096-7780 CN 10-1665/P

土层地震反应计算选用模型与输入界面影响的研究

Discussion on the influencing factors of seismic response calculation of soil layer

  • 摘要: 本文选用H-D模型和Davidenkov模型对土层动力试验本构参数进行拟合,讨论了本构模型对土层地震反应计算的影响;选取Ⅱ、Ⅲ、Ⅳ类场地各一个土层剖面,选定500 m/s剪切波速的界面作为地震动输入界面,下伏土层考虑为与输入土层性质一致,向下取5~30 m的6个输入界面,选用Imperial Valley波、Northridge波以及Kobe作为输入地震动,用一维等效线性化方法进行计算,分析了输入界面选取对土层地震反应计算的影响。通过对结果的分析得出:① Davidenkov模型对于软土拟合优度优于H-D模型,但两者拟合得到的土层地震动反应区别较小,仅在0.40 g幅值输入情况下PGA表现出一定差别。② 地表峰值加速度在下伏土层一定厚度内随着深度增加而增大;地表加速度反应谱下伏土层一定厚度内随着深度增加在短周期减小,在长周期和波峰增大。③ 土层地震反应分析在选定500 m/s剪切波速为钻孔终层和输入界面时,宜考虑5~20 m厚的与终层性质相同的下伏土层作为输入界面。

     

    Abstract: In this paper, H-D model and Davidenkov model were used to fit soil layer parameters, and the influence of constitutive model on seismic response calculation of soil layer was discussed. It Select one soil layer profile in each of the sites of class Ⅱ, Ⅲ and Ⅳ, and select the interface of shear wave velocity 500 m/s as the ground motion input interface. The underlying soil layer is considered to be consistent with the input soil layer, and 6 input interfaces of 5~30 m are taken downward. Imperial Valley wave, Northridge wave and Kobe wave were selected as input ground motion were calculated by one-dimensional equivalent linearization method. The influence of input interface selection on soil layer seismic response calculation was discussed. Through the analysis of the results obtained: ① The goodness of fit of Davidenkov model is better than H-D model for soft soil, but there is little difference in ground motion response obtained by the two models. PGA only shows a certain difference under the input of 0.40 g amplitude. ② The peak acceleration of the surface increases with the increase of depth within a certain thickness of the underlying soil layer. Within a certain thickness of ground surface acceleration response spectrum, it decreases with increasing depth in short period, and increases with increasing wave peak in long period. ③ Site seismic response analysis when the shear wave velocity of 500 m/s is selected as the final layer and input interface of the drilling hole, it is appropriate to consider the underlying soil layer of 5~20 m thickness with the same property as the final layer as the input interface.

     

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