| 摘要: |
| 对程星磊等提出的总应力形式增量弹塑性本构模型进行二次开发，以模拟复杂应力状态下软黏土的响应。通过Newton Raphson算法，对材料非线性问题进行迭代求解；针对本构模型中应力反向等一系列关键性问题，应用欧拉切线算法编写了有限元程序，并结合子增量方法提高了计算精度。预测了软黏土在轴对称应力状态下的响应，得到了应力应变关系曲线，将其与单元预测结果进行比较，二者趋于一致，从而验证了有限元程序编写的合理性。利用该程序模拟三轴不固结不排水试验，模拟结果与试验吻合良好，表明该本构模型有限元程序可以反映轴对称应力状态下软黏土的不排水应力应变特性，可应用于更加复杂边值问题的模拟计算。 |
| 关键词: 循环荷载 饱和软黏土 应力应变 本构模型 欧拉切线算法 三轴试验 |
| DOI： |
| 分类号:TU43 |
| 基金项目:国家自然科学基金资助项目（51179120）；博士点基金项目（20130032110045） |
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| Numerical simulation of undrained cyclic stress-strain response of soft clay |
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WANG Zhe-xue1,2, WANG Jian-hua1,2, CHENG Xing-lei1,2
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1.State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University;2.Geotechnical Engineering Institute, Tianjin University
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| Abstract: |
| An incremental elasto-plastic constitutive model in the form of total stress developed by CHENG Xing-lei et al can effectively reflect the undrained cyclic stress-strain response of the saturated soft clay. In order to simulate the response of the soft clay under complex stress states，a secondary development for the constitutive model is conducted by use of the finite element method. The Newton-Raphson method is applied to solve iteratively the material nonlinear problem; considering a series of key problems such as stress reversing, in programming the model, Euler tangent algorithm is adopted，with a sub-incremental method improving calculation accuracy. The response of the soft clay under axisymmetric stress states is predicted, and the stress-strain relationship curves are received, which is compared with the results given by the unit predicting. The analysis comparison results show that it is in good agreement, verifying the rationality of the finite element program. The finite element program is applied to simulate unconsolidated undrained triaxial tests， and the results are in good agreement with the experiments, which indicates that the finite element program of the constitutive model can describe the undrained stress-strain behavior of the soft clay under triaxial stress states. Furthermore, it can be applied to solve more complex boundary value problems. |
| Key words: cyclic load saturated soft clay stress strain curve a constitutive model Euler tangent algorithm triaxial tests |
