论文部分内容阅读
为了描述天然软土的时间相依以及结构性特征,提出了一种能考虑土体超固结和结构性的实用弹黏塑性本构模型。它以Asaoka和Hashiguchi的上下负荷面作为某一应变速率下的参考屈服面,按照相对过应力的基本思路,新引入了两个能通过不同应变速率三轴压缩试验测定的率敏性参数c_0和m’,建立了以当前应力、黏塑性应变以及黏塑性应变速率为状态变量的动屈服准则函数,并给出了基于Newton-Raphson迭代的应力积分算法,且成功地将其嵌入到大型有限元软件ABAQUS中。最终通过数值算例来验证模型的正确性以及应力积分算法的可靠性。结果表明:该模型能同时描述土体的率敏性、蠕变以及结构性特征,模型参数物理意义明确、易懂可测,预测结果与试验数据吻合良好,可用于复杂边值问题的有限元计算。
In order to describe the time-dependent and structural characteristics of natural soft soils, a practical visco-elastic constitutive model considering the overconsolidation and structural properties of soils is proposed. Taking Asaoka and Hashiguchi upper and lower load surfaces as the reference yield surface at a certain strain rate, two new rate-sensitivity parameters c_0 and t_0, which can be measured by triaxial compression tests at different strain rates, were introduced according to the basic concept of relative stress. m ’, the dynamic yield criterion function of current stress, viscoplastic strain and viscoplastic strain rate as state variables is established, and the stress integration algorithm based on the Newton-Raphson iteration is given, and it is successfully embedded into the large finite element Software ABAQUS. Numerical examples are finally used to verify the correctness of the model and the reliability of the stress integration algorithm. The results show that the model can simultaneously describe the rate sensitivity, creep and structural characteristics of the soil. The physical meaning of the model parameters is clear, understandable and measurable. The predicted results are in good agreement with the experimental data and can be used in the finite element analysis of complex boundary value problems Calculate.