砂土管涌的反滤机理颗粒流模拟研究

Study on the Sand Piping Filtering Mechanism Based on PFC

针对反滤料粒径对反滤效果的影响,采用颗粒流程序建立不同层间系数基土-滤层颗粒模型,并进行渗流模拟。分析比较不同层间系数下反滤层的滤土减压效果表明,在所给范围内,当层间系数D_(15)/d_(85)~*<4时,滤土减压效果较好;当D_(15)/d_(85)~*>4时,减压效果虽较好,但滤土作用差。颗粒流数值模拟结果与滤层准则经验公式一致。

To study the influences of the particle size on filtering effect,particle models of the bed soil-filter layer with different interlayer coefficients are established using the particle flow code（ PFC）. The seepage simulation results show that the soil particle filtering effect and the seepage pressure relief performance of the filter layer are both satisfactory when the interlayer coefficient or the representative particle size ratio D15/d85^＊is less than 4. When the interlayer coefficient D15/d85^＊ is greater than 4,the seepage pressure relief performance of the filter layer is good while the filtering effect is poor. The numerical simulation results are consistent with the empirical formula of filter layer criteria.