软土初始应力各向异性弹塑性模型

自然土体处于初始应力状态,其强度和应力-应变关系都呈现出各向异性,而以往广泛使用的剑桥模型是建立在重塑土试验结果的基础上的,因此,计算实际问题时有一定缺陷.在总结了一些在修正剑桥模型基础上进行扩展而得到的各向异性模型,尤其是S-CLAY1模型.然后,假定了初始屈服面的倾角为K0线,这样使S-CLAY1的计算更加简单.此外,还编制了相关程序,进行了比较计算.结果表明,该模型简单合理,参数正确,可以在实际工程中应用.

An elastoplastic model for soft clays with initially stress-induced anisotropy

Natural soft clays tend to have a significant degree of anisotropy in both shear strength and stress-stain relationship due to its anisotropic consolidation. Although the modified Cam-Clay model has been widely used, it was developed based on the laboratory test data of remolded clays. Therefore, it is in fact not suitable for the analysis of practical engineering cases. Firstly, this paper summarized anisotropic elastoplastic models generalized from the modified Cam-Clay model in the literature, especially S-CLAY1 model originally proposed by Wheeler(1997). A simplified S-CLAY1 model with the assumption of the yield surface along the K0-line is then outlined. Finally, the model is numerically implemented; and comparisons between simulations and experimental results are given. It is demonstrated that the model predictions compare favorably with experimental data and provide a useful constitutive framework for engineering due to its simplicity.