均匀湿颗粒材料边界滞回持水曲线的物理模型

A physical hysteresis boundary water retention model for uniform wet particulate material

非饱和土持水特性的滞回机理是土力学界的热点问题之一。将非饱和土看作"湿颗粒材料"并以"土-颗粒-系统"为视角更易认识其持水特性的滞回机理。以均匀湿颗粒材料为研究对象,用轴对称圆锥形孔隙内水分的充填和排出过程来模拟边界增、减湿过程,提出一种物理模型以描述其滞回特性的物理内涵,并利用已有文献中3种砂土和2种含黏砂土的持水试验结果验证了该模型在表征均匀湿颗粒材料边界滞回持水曲线时的有效性。该模型的优点在于不仅对同种均匀湿颗粒材料滞回的边界减、增湿持水曲线可采用同一组具有物理意义的参数模拟,而且可反映孔隙水内封闭气泡对持水曲线的影响。

Hysteresis mechanism for water retention behavior is increasingly concerned by unsaturated soil mechanics researchers. It is easier to cognize the essence of this mechanism for wet particulate material such as unsaturated soil, from the perspective of ＂soilparticlesystem＂. A physicalwater retention model is proposed for uniform wet particulate material, where boundary wetting and drying processes are considered to he the filling and draining processes of assumed symmetrical coneshaped pores. The model is then veri fied using the retention data for three sands and two clayed sands in the past literature. In summary, the advantage of this model is that all model parameters, which have definite physical base, behave unique for hysteresis boundary retention curves, and the influence of the closed air huhbIes in pore water is also con sidered.