Research On Capillary Motion Model Based On Jurin Criterion

Capillary water rise is an important manifestation of infiltration and plays an important role in engineering applications.The rise of capillary water can significantly affect the soil moisture content and cause engineering problems such as roadbed frost damage,soil salinization,and reduced foundation strength.The Jurin criterion is a classic calculation model for predicting the rise height of capillary water,but its predicted value has a significant error compared to the actual rise height of capillary water,which is closely related to the oversimplification of the mechanical model and the selection of key parameters such as solidliquid contact angle.This article studies the law of capillary water rise in quartz capillaries through theoretical derivation and indoor related experiments,The main research results are as follows:(1)Considering the adsorption force and frictional resistance of capillary walls on capillary water,the Jurin criterion was improved and a mathematical model based on energy conservation was derived to calculate the height of capillary water rise.After verification,the improved Jurin criterion has an average error rate of 7.1%(2)By using a self-designed quartz capillary friction coefficient measuring device,a capillary water rise test with a fixed head height and initial kinetic energy was conducted,and the friction coefficient of quartz capillary against capillary water was determined based on the principle of energy conservation.(3)Through indoor capillary water rise experiments and IPP image analysis software,explore the variation law of contact angle during capillary water rise process.Research has found that the contact angle during the rise of capillary water is not a fixed value but gradually decreases,and after the maximum height of capillary water rises,the contact angle does not immediately stop but continues to decrease over time until it reaches a stable state.(4)For quartz capillaries ranging from 0.2mm to 1.0mm,the maximum height of capillary water increases with the increase of pipe diameter,showing a decreasing trend overall.The critical pore size for the rise height of capillary water is 0.4mm,under which the curved surface of capillary water is in a liquid bridge state,and its capillary driving effect is the strongest.