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天然土体的初始各向异性通常可对其后继循环特性产生显著影响。现有考虑循环载荷作用的土体弹塑性模型,往往采用类似修正剑桥模型的椭圆形屈服面,已有研究表明,该椭圆形屈服面因其拉伸弹性区域偏大,针对天然K0固结状态的土体,其计算精度较差。基于新近提出的广义各向同性硬化准则,在边界面方程中引入初始各向异性张量,并采用空间滑动面破坏准则(SMP)的变换应力法,建立了能考虑饱和黏土初始各向异性的循环边界面塑性模型。分别针对等压和偏压固结的饱和黏土静、动三轴试验进行模拟,结果表明,该模型能合理反映土体的初始各向异性及其后继循环动力特性。
The initial anisotropy of natural soils can often have a significant effect on their subsequent cycling characteristics. The existing elastic-plastic model of soils considering cyclic loading usually adopts the elliptical yield surface similar to the modified Cambridge model. It has been shown that the elliptical yielding surface is large due to its large tensile elastic area. For the natural K0 consolidation state Of the soil, its calculation accuracy is poor. Based on the newly proposed generalized isotropic hardening criterion, the initial anisotropic tensor is introduced into the boundary surface equation and the transformation stress law of the space sliding surface failure criterion (SMP) is adopted to establish the initial stress anisotropy Cyclic boundary plastic model. The static and dynamic triaxial tests of saturated clay under isobaric and bias consolidation are simulated respectively. The results show that the model can reasonably reflect the initial anisotropy of soil and the dynamic characteristics of its subsequent cycles.