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在Wheeler本构模型框架的基础上,提出了一个水力与力学耦合的本构模型。该模型中的土-水特征曲线采用毛细滞回内变量模型,能够更好地描述水力历史变化下毛细滞回现象对非饱和多孔介质变形的影响,同时也可描述非饱和多孔介质变形对渗流的影响。非饱和土的强度不仅与吸力有关,而且受到饱和度的影响。相同的吸力下,土样经过吸湿和脱湿路径的饱和度不同,因此,非饱和土的强度也不同。此模型以体积含水率的塑性变化和体变的塑性变化为硬化参数,不仅能描述基质吸力对非饱和土的强化作用,而且考虑了饱和度对强度及变形的影响。试验结果与模型预测基本吻合,证明该模型能够模拟非饱和土的主要特性。为了简化,此模型是在各向同性荷载下推得的,有待于推广到一般的应力状态。
Based on the framework of Wheeler constitutive model, a constitutive model coupled with hydraulics and mechanics is proposed. The soil-water characteristic curve in this model uses the capillary hysteretic internal variable model to better describe the effect of capillary hysteresis on the deformation of unsaturated porous media under the hydraulic history, and to describe the effect of unsaturated porous media deformation on seepage Impact. Unsaturated soil strength is not only related to suction, but also affected by the saturation. Under the same suction, soil samples have different degrees of saturation through the path of moisture absorption and desorption, so the strength of unsaturated soil is also different. This model takes the plastic change of volumetric water content and the plastic change of bulk change as the hardening parameters, which can not only describe the enhancement of matrix suction on unsaturated soil, but also consider the effect of saturation on strength and deformation. The experimental results are basically consistent with the model prediction, which proves that the model can simulate the main characteristics of unsaturated soils. For simplicity, the model is derived under isotropic loading and needs to be generalized to general stress conditions.