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多孔介质中的流动问题,与孔隙介质的特性,含水量状态以及含水量的变化历史密切相关。基于毛细循环滞回理论模型,考虑含水量变化历史对土水特征关系的影响,在开发的U-DYSAC2有限元程序中进行了相应的数值实施。在试验给定的初边值条件下进行了非饱和渗流模拟分析,并将模拟结果与实测数据比较,表明在压力边界条件反复变化下,考虑滞回效应能获得更接近实测的结果,证实该模型在模拟各种循环变化条件下非饱和土渗流初边值问题的适用性与必要性。对入渗重分布反复变化条件下非饱和土柱流动的数值模拟表明,考虑滞回与不考虑滞回条件下,含水量、孔隙水压力和湿峰的迁移的预测在入渗后的重分布过程差异较大。考虑滞回效应时,土柱上部的脱湿速率、下部的吸湿速率比不考虑滞回时要低。从而证实了非饱和多孔介质中的土水状态依赖于含水量变化,而且强烈依赖于土体的水力路径变化。因此,循环边界条件变化下,毛细滞回效应在非饱和渗流模拟中的影响显著,必须加以考虑。
The flow problem in porous media is closely related to the characteristics of porous media, the state of water content and the history of water content changes. Based on the theoretical model of capillary cycle hysteresis and considering the influence of the history of moisture content on the relationship between soil and water characteristics, a corresponding numerical implementation was carried out in the developed U-DYSAC2 finite element program. Unsaturated seepage simulation analysis is carried out under the given initial boundary conditions. The simulation results are compared with the measured data, which shows that under the repeated changes of pressure boundary conditions, the hysteresis effect can get closer to the measured results, Applicability and Necessity of the Model in Permeating Initial Boundary Value of Unsaturated Soil under Various Cyclic Changes. The numerical simulation of unsaturated soil column flow under repeated changes of infiltration re-distribution shows that the prediction of the migration of moisture content, pore water pressure and wet-peak after hysteresis and without considering hysteresis is redistributed after infiltration The process is quite different. When considering the hysteretic effect, the upper dehumidification rate and lower moisture absorption rate of soil column are lower than those without hysteresis. It is confirmed that the state of soil-water in unsaturated porous media depends on the change of water content and strongly depends on the change of hydraulic path of soil. Therefore, the effect of capillary hysteresis in the unsaturated seepage simulation under the change of cyclic boundary conditions is significant and must be considered.