在往复水流中进行土工织物反滤层稳定性的试验分析

Test analysis on the seepage stability of the soil-geotextile filtration under cyclic flow

通过自行研制的循环往复水流试验装置,分别对不同频率的正弦水流与较大孔径土工织物反滤层所组成的反滤系统的渗透稳定性进行了试验分析。结果表明:当土工织物孔径与土颗粒特征粒径d85的比值达到8.57时反滤系统仍然能够保持渗透稳定性;增大循环往复水流的频率或振幅,将减小反滤系统的渗透稳定性;随着往复周期的减小,产生水力梯度边界集中现象,容易加剧渗透边界层的冲刷,降低反滤系统的渗透稳定性。

A cyclic flow model of the filter test was developed to study the seepage stability of the back-filtration systems made up of sine flow with different frequency and back-filtration of geotextiles with bigger pore diameter. Test results show that the seepage stability of the back-filtration system could still be maintained when the ratio of opening size of filtration net and characteristic grade size ds5 of soil was 8.57, higher frequency and swing of the periodic flow led to higher instability of the back-filtration system. Lower frequency of the periodic flow bring hydraulic gradient focusing, which will lead to more filtration border erosion and diminish the stability of the back-filtration system.