三维应力空间下改进状态变量的上下负荷面模型及其数值实现

为准确描述结构性土、超固结土的复杂弹塑性力学行为,对上下负荷面模型中的超固结状态变量R与结构性状态变量R*的演化规律进行改进,运用Sheng建议的破坏准则把模型的应用范围拓宽到三维应力空间,建立了三维应力空间下改进状态变量的上下负荷面模型。详细介绍了该模型隐式应力更新算法的数值实现过程,编制了对应的接口子程序,实现了对有限元软件的二次开发,并通过一系列数值模拟验证了模型的合理性、程序的精度与稳定性。最后应用本文模型模拟Boom黏土和Fujinomori黏土并与试验数据对比,结果表明,模型能够准确描述结构性土、超固结土的力学特征。

Super-subloading surface model with improved state variables in 3D stress space and its numerical implementation

A 3D improved super-subloading surface model is established to discribe the complex behaviors of overconsolidated and structured soil precisely. By comparing with those of the existing super-subloading surface models, the evolution of overconsolidation state variable R and structural state variable R* in this model is ameliorated. Moreover, the realm of the model is expanded to 3D stress space as the shape of yield condition in π plane is assumed to be sleeked by utilizing the failure criterion suggested by Sheng. Then the procedure of implicit stress-update algorithm is introduced, and the model is realized in finite element software by subroutine. Subsquently, the rationalities of the model and the subroutine are verified in a series of numerical simulations. Finally, Boom clay and Fujinomori clay are simulated, and the numercial simulation results are compared with the test data. The comparison shows that the proposed model can describe the characteristics of overconsolidated and structured soil accurately.