两种塑料排水板滤膜淤堵特性试验研究

在水力梯度逐级递增的条件下,采用饱和软黏土进行了两种不同塑料排水板(PVD)滤膜(外包土工织物)梯度比试验,探讨两种PVD滤膜的淤堵特性,并结合真空预压软基加固的实际工况进行分析。试验结果显示,随着水力梯度的递增,一种表观孔径大的新工艺PVD滤膜的梯度比呈现先上升后下降的总趋势,并最终趋于稳定,常规PVD滤膜的梯度比总体呈上升趋势,无法趋于稳定。研究表明,不同水力梯度对滤膜淤堵有着较大影响,新工艺PVD滤膜在真空预压实际工况(水力梯度较高)下的防淤堵效果优于常规PVD滤膜。PVD滤膜的淤堵问题与滤膜制作工艺、孔径和软黏土性质有关,其淤堵机制仍需进一步的研究。

Experimental research on clogging characteristic of two types of PVD filters

Gradient ratio tests of two kinds of plastic vertical drain (PVD) filters (wrapped geotextile) are carried out under the condition of hydraulic gradient increased step by step in the environment of saturated soft clay. Combined with actual vacuum preloading working conditions of soft foundation treatment, the clogging characteristics of two kinds of PVD filters are analyzed. Experimental results show that, with increasing hydraulic gradient，gradient ratio of the anti-clogging effect of the new PVD filter with larger apparent opening size shows upward trend firstly, then downward trend, eventually stability, while gradient ratio of the traditional PVD filter shows upward all the time and is unable to stabilize. Research results show that different hydraulic gradients have a great influence on the clogging features of the PVD filters; and the new PVD filter is better than that of the traditional one in actual vacuum preloading working conditions (the hydraulic gradient is high). The clogging of PVD filters relates to the production technology, pore size of the filter and characteristic of soft clay; it is required to deepen the research of the clogging mechanism of filters.