结构性土UH模型

在描述重塑土的统一硬化模型（UH模型）基础上，以动态地移动正常固结线（MNCL）代替静态的正常固结线（NCL）作为参考线来确定参考应力，将土的结构性衰减体现在MNCL的演化中，从而把UH模型扩展为可考虑土结构性的结构性土UH模型。结构性土UH模型可以合理地并连续光滑地描述结构性土的等向压缩规律、应变硬化、应变软化、剪切体积收缩、剪切体积膨胀、不排水剪切减压软化以及结构性和密度耦合影响等力学特性。相比于UH模型，结构性土UH模型新增3个参数，分别用于描述结构性的程度、衰减速度、以及塑性流动规律。通过3种天然土的试验结果与模型预测对比验证了结构性土UH 模型的合理性。

A UH constitutive model for structured soils

Based on the unified hardening (UH) model of reconstituted soil, a UH constitutive model is developed for structured clay. In this model, the dynamically moving normal consolidation line (MNCL) instead of the static normal consolidation line(NCL) is used as the reference line in determining the reference stress; and a proper increment evolution equation is proposed for the MNCL to describe the soil structural decay. The proposed structured soil UH model can reasonably simulate many behaviors of the structured soil, including the isotropic compression, strain hardening, strain softening, shear-induced shrinkage, shear-induced expansion, undrained shear decompression softening and coupling effect between soil structure and soil density. Compared to the original UH model, the structured soil UH model includes 3 new model parameters, which reflect the soil structure degree, the structure decay rate and the plastic flow rule, respectively. Comparisons between the test results and the model predictions of the three natural soils indicate that the structured soil UH model can reasonably describe the main features of the behavior of the structured soil.