反滤层滤网孔径对砂土颗粒概率渗流流失量影响的研究

Research on Influence of Pore Sizes for Filter Clothes in Inverted Layers on Probabilistic Seepage Loss for Sandy Soil Particles

对渗流过程中砂土渗流孔隙管道中的土颗粒进行受力分析,基于颗粒的概率过网准则,综合考虑反滤层滤网孔口的孔径和丝径、水力坡降、土颗粒级配、密实度、内摩擦角对土颗粒渗流流失量的影响,建立了砂土土颗粒概率渗流流失量的计算方程。在不同滤网孔径的条件下,对北京永定河所取得的砂土进行了径向渗透试验,收集了试验过程中土颗粒的流失量,并将试验结果与土颗粒概率渗流流失量方程的计算结果进行对比,表明两者较为吻合。可以得出滤网孔径与砂土径向渗透系数以及土颗粒流失总量呈正相关的结论;所建立的土颗粒概率渗流流失方程可以较好地计算出砂土土颗粒在滤网作为渗出边界条件下的渗流流失量。

The stress of soil particles in seepage pore channels of sand in penetration processes was analyzed.Based on the criterion for the probability of particles across filter clothes,comprehensively considering the influence of pore sizes for filter clothes in inverted layers and filter wire diameters,hydraulic slopes,grain size distribution,densities and angles of internal friction on the seepage loss of soil particles,the equation for soil particle seepage loss of sand soil based on the probability was established.The radial permeability tests of sandy soil from Yongding River in Beijing were conducted in the conditions of different pore sizes for filter clothes,and the loss of soil particles in tests were collected.The test results were compared with the calculated results by the seepage loss equation of soil particles,and the two were consistent.It could be regarded that the size of filter clothes was positively correlated with the radial permeability coefficient of sandy soil and the soil particle loss.The established seepage loss equation of soil particles based on the probability could be better calculated the seepage loss of sandy soil particles in the condition for the seepage boundary of filters.