土壤渗流中渗透系数与液桥力关系研究

Study on the relationship between permeability coefficient and liquid bridge force in soil seepage

为了研究土壤渗流速度的动态变化过程,借助渗透率动态测试装置,监测渗透系数在不同水头作用下的变化趋势。采用计算流体力学与离散单元(CFD-DEM)数值分析方法,结合应用程序接口(API)二次开发功能,实现颗粒之间随着水分增加而产生液桥力的过程,分析颗粒之间的液桥力对渗流速度的影响。结果表明:不同水头下,测试的土壤渗透系数随着时间的延长而降低,相比于颗粒堆积方法分析渗流过程中渗透系数的变化情况,通过API加入液桥力,颗粒的粘结作用增强,渗透系数呈现与实验一致的变化过程,证明液桥力是导致渗流过程中渗透系数突然降低的一个影响因素。

In order to study the dynamic change process of permeability velocity during soil seepage process,the permeability dynamics test device was used to monitor the change trend of permeability coefficient under different water heads.At the same time,the CFD-DEM numerical simulation analysis method combined with the API secondary development function was used to analyze the liquid bridge force caused by the increase of water content between the particles.The permeability coefficient was decreased with time under different water heads.The soil model of common particle accumulation was difficult to analyze the change of permeability coefficient during the seepage process.After the API application,the particle adhesion under the action of the liquid bridge force was enhanced.And the same change process of permeability coefficient was found by using the API function as in the experiment.Therefore,liquid bridge force was one of influencing factors which caused a sudden decrease in the permeability coefficient during the seepage process.