粗粒土初始各向异性弹塑性模型

摘要

On the basis of the former study on anisotropy of fine-grained soil, an elastoplastic model applicable for coarse-grained soil was proposed. The improved yield surface of this model is a rotational ellipse. Two hardening parameters which consider the plastic volumetric strain coupling to plastic shear strain are adopted in this model, that is, the hardening parameter k0, which is related to the size of the yield surface of model, and the rotation hardening parameter a. The presented model can reflect the dilatancy of coarse grained soil in the initial and the subsequent anisotropy state preferably. K0 consolidated drained and K0 consolidated undrained tests are carried out by making use of a gravel soil that is taken from ShuanJiangKou earth dam, and the model is validated by comparing the predicted results with the test data. As it turned out, the model can rationally predict the stress-strain behaviour of coarse-grained soil.%基于黏土的初始各向异性研究成果,提出一个适用于粗粒土的弹塑性模型.该模型屈服面为旋转的椭圆,采用考虑塑性体应变和塑性剪应变耦合的两个硬化参数,即表示屈服面大小的硬化参数κ0和旋转硬化参数α.模型能较好地反映初始及后续各向异性状态下粗粒土的剪胀性.利用双江口堆石坝覆盖层砂卵砾石料,进行了岛固结排水剪和K0固结不排水剪大三轴试验,并用试验结果对模型进行了初步验证.研究结果表明:模型能够合理地预测粗粒土的变形和强度特性.