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基于热力学内变量理论,提出能综合考虑毛细滞回效应和非饱和土体积变形影响的土-水特征曲线模型。热力学第二定律推导结果表明:毛细滞回现象和塑性变形本质上是一种耗散行为;吸力和饱和度的变化不仅与流相变化直接相关,而且也受到固相体积变化的约束与影响;土-水特征曲线的流相体积变化与固相变形之间存在相互耦合作用。从微观上阐明滞回现象产生的机制以及变形对吸力的影响,建立了考虑体变及滞回效应的土-水特征曲线一般性模型。然后采用边界面塑性理论,在只增加两个新参数的情况下,建立了一个简化的能描述毛细滞回及塑性孔隙比变化影响的新模型。最后,利用已有试验数据对这一模型进行了验证,结果表明,新模型能考虑土体变形的影响,并能较为准确地描述毛细滞回现象,模型预测结果与已有的试验数据吻合较好。
Based on the theory of internal variables in thermodynamics, a soil-water characteristic curve model considering the effects of capillary hysteresis and volume deformation of unsaturated soils is proposed. The results of the second law of thermodynamics deduced that the phenomenon of capillary hysteresis and plastic deformation are essentially dissipative behavior. The changes of suction and saturation are not only directly related to the change of phase but also influenced by the volume change of solid phase. There is a mutual coupling between the phase volume change of the soil-water characteristic curve and the solid phase deformation. The mechanism of hysteretic phenomena and the effect of deformation on suction are clarified microscopically. A general model of soil-water characteristic curve considering volume change and hysteretic effect is established. Then, using the plasticity theory of boundary surface, a new simplified model that can describe the effect of capillary hysteresis and plastic porosity ratio is established with only two new parameters added. Finally, the model is verified by using the existing experimental data. The results show that the new model can consider the effect of soil deformation and describe the capillary hysteresis more accurately. The predicted results are in good agreement with the existing experimental data it is good.