Computational modeling of cyclic mobility and post-liquefaction site response
Computational modeling of cyclic mobility and post-liquefaction site response
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DOI：
10.1016/s0267-7261(02)00022-2
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发表时间：
2002-06
影响因子：
4
通讯作者：
A. Elgamal;Z. Yang;E. Parra
中科院分区：
文献类型：
--
作者：
A. Elgamal;Z. Yang;E. Parra
在地震激励下，液化干净的中等至致密的无粘性土可以在大的剪切应变偏移时恢复高水平的抗剪性。这种反应模式被称为循环流动性的一种形式，已被大量的实验室样品测试和离心实验记录在案。建立了基于塑性的本构模型，重点模拟了循环流度响应机制和剪切应变累积模式。本构模型被纳入一个两相（固体-流体），完全耦合的有限元代码。本构模型的校准描述，基于一套独特的实验室三轴试验（单调和循环）和动态离心实验。在该实验系列中，采用相对密度约为40%的内华达州砂。校准工作的重点是再现循环流动性机制所决定的动态场地响应的显着特征。最后，利用标定的模型，进行了数值模拟，突出的激励频率含量对液化后地面变形的影响。
Under seismic excitation, liquefied clean medium to dense cohesionless soils may regain a high level of shear resistance at large shear strain excursions. This pattern of response, known as a form of cyclic mobility, has been documented by a large body of laboratory sample tests and centrifuge experiments. A plasticity-based constitutive model is developed with emphasis on simulating the cyclic mobility response mechanism and associated pattern of shear strain accumulation. This constitutive model is incorporated into a two-phase (solid–fluid), fully coupled finite element code. Calibration of the constitutive model is described, based on a unique set of laboratory triaxial tests (monotonic and cyclic) and dynamic centrifuge experiments. In this experimental series, Nevada sand at a relative density of about 40% is employed. The calibration effort focused on reproducing the salient characteristics of dynamic site response as dictated by the cyclic mobility mechanism. Finally, using the calibrated model, a numerical simulation is conducted to highlight the effect of excitation frequency content on post-liquefaction ground deformations.