摘要
对西藏山南地区水库坝基材料进行渗透淤堵室内试验及颗粒流数值模拟,从宏观到细观的角度研究了坝基松散介质渗透淤堵的过程。室内试验采用自制的渗透淤堵装置,分别对不添加淤堵材料及添加粒径为0.075～0.5mm、0.5～1mm淤堵材料的试样进行渗透淤堵试验,并监测试样的流速及渗透系数。试验结果表明:(1)添加粒径为0.5～1mm淤堵材料的试样流速降低速率较快,达到稳定后的流速值较低;(2)两种淤堵材料均可达到淤堵效果,添加粒径为0.5～1mm淤堵材料的试样渗透系数降低较快,淤堵颗粒流失量较小。数值模拟记录了淤堵过程中流速、渗透系数及孔隙率的变化情况,并监测了淤堵颗粒中单个颗粒运动速度及位置的动态变化过程。计算结果显示:(1)随着时步增加,模型试样的孔隙率逐渐降低,添加粒径为0.5～1mm淤堵材料的试样的流速降低相对较快且淤堵颗粒流失量较少;(2)对于无淤堵材料的试样渗透系数变化曲线随时步迅速收敛,而对于添加了两种淤堵材料的试样渗透系数变化曲线随时步呈递减趋势,并最终趋于稳定,透水性能降低,产生淤堵效应;(3)在渗透淤堵过程中淤堵颗粒的运动具有随机性。数值模拟结果与室内模拟试验所得的结果基本一致。
The infiltration clogging process of loose dam foundation was studied from macroscopic to the microcosmic aspects by using PFC3D software and the indoor model tests.The tests＇samples were taken from the riverbed of Zhuoyu Reservoir in Tibet.In model test,fluid velocity and coefficient of permeability of the specimen were monitored under three conditions,by adding clogging materials to the specimens with particle size of 0.5~1mm and 0.075~0.5mm,respectively,and a specimen with no clogging materials using infiltration clogging instrument by ourselves.The results show that：（1） the rate of fluid velocity with clogging materials of particle size in 0.5~1mm was reduced faster and gotten lower value than another specimen with clogging materials;（2） Clogging effects occurred both in the specimens with adding two kinds of clogging materials.The permeability coefficient of specimen with clogging materials of particle size in 0.5~1mm decreases more rapidly with lower material loss than that that of specimen with adding clogging of particle size in 0.075~0.5mm.In numerical simulation,the values of fluid velocity,permeability coefficient,porosity of specimens and velocity,position of single movable particle was calculated in the infiltration clogging process.The velocity and position of single particle were also analyzed.The results of the calculation reveal that：（1） the porosity of specimen gradually decreased with time step increased,the rate of fluid velocity of specimen with clogging materials in 0.5~1mm was reduced faster and has lower material loss than that of specimen with clogging material in 0.075~0.5mm;（2） permeability coefficient of specimens with adding two clogging materials gradually decreases with time step increased and finally stabilized to a low permeability,which indicating clogging effect in specimens;（3） clogging particle motion has randomness and uncertainty in infiltration clogging process.Numerical simulation results and model test results are basically coincident.
出处
《水利学报》
EI
CSCD
北大核心
2012年第10期1163-1170,共8页
Journal of Hydraulic Engineering
基金
国家自然科学基金面上项目(41072191
40972171)
关键词
淤堵效应
颗粒流
松散土坝基
水库
clogging effect
particle flow
loose dam foundation
reservoir
