不等径湿颗粒与液桥相互作用的微观水力特性

Microscopic hydraulic behavior from the interactions between uneven-sized wet particles and liquid bridge

从土颗粒的微观尺度认识和解释非饱和土的基本性质已成为土力学界日益关注的课题之一,将非饱和土作为湿颗粒材料来研究湿颗粒与液桥的相互作用更易认识其内在的微观水力特性。为研究一对不等径湿颗粒间形成液桥时表现的微观水力特性,用相应的光滑球体颗粒的间距描述颗粒表面的粗糙度,假定液桥的形状为圆环且不考虑颗粒重力和浮力的影响,提出了表征这对湿颗粒与液桥相互作用的理论模型。随后研究了液桥体积和毛细作用力与基质吸力、颗粒半径比、固-液接触角、颗粒表面粗糙度的无量纲关系,而且分析了干燥条件下颗粒间液体和液体蒸汽间的平衡关系。最后利用已有文献对球体颗粒间液桥的毛细作用力实测值验证了该模型在表征液桥毛细作用力与颗粒间距关系时的有效性。

Soil particlelevel investigation of basic behavior for unsaturated soil is increasingly concerned by soil mechanics researchers. It seems easier to recognize microscopic hydraulic behavior of wet particulate material such as unsaturated soil by analyzing the interaction between wet particles and liquid bridge. A the oretical model for the interaction between unevensized wet particles and liquid bridge is proposed, consist ing of an assumed toroidshaped liquid bridge in contact with corresponding smooth particles, at a separa tion determined by their actual surface roughness. The volume and capillary force of the liquid bridge be tween them are related to matrie suction, ratio of particle radius, solidliquid contact angles, and rough ness of the particles. In addition, equilibrium between liquid and liquid vapor is also analyzed. Finally, the model can be in good accordance with the test data of capillary force versus particle separation in the past literature.