泥浆真空抽滤泥水分离中堵塞机理及规律性研究

发布时间：2018-11-05 19:54

【摘要】：河湖底泥的疏浚工程因为使用绞吸式的疏浚方式,底泥与水混合后变成大量高含水率的泥浆。为了减少泥浆的体积,对泥水进行分离就显得非常重要。在将泥浆中水分抽滤分离的过程中,经常会发生堵塞,产生了抽滤效果低,抽滤不能持续的问题。针对这一问题,研究了不同泥浆粒径分布、泥浆的初始含水率、土工布的孔径、真空负压以及添加絮凝剂对泥水分离效果的影响,探讨了堵塞的机理。发现了由土工布过滤形成的泥皮的渗透系数将成为制约脱水效果的主要因素,当形成堵塞性泥皮时,其他因素如土工布的孔径、泥浆初始含水率等对脱水的影响可以忽略。添加絮凝剂会使颗粒聚团从而提高泥皮渗透系数是泥水分离变好的原因,并且絮凝泥浆中较小的团粒粒径决定了泥皮的渗透系数,因此可以通过检测絮凝后泥浆中较小团粒的粒径如D_(10),D_(15),D_(20)的方式比选絮凝剂、决定最优添加量、预测脱水效果。添加絮凝剂对泥浆中结合水含量的改变影响较小,因此认为絮凝使水分结合方式的改变并不影响泥水分离的效果。
[Abstract]:In the dredging engineering of river and lake sediment, the mixing of sediment and water becomes a large amount of mud with high moisture content. In order to reduce the volume of mud, it is very important to separate mud water. In the process of separating water from mud, blockage often occurs, which leads to the problem of low filtration effect and unsustainable drainage. In order to solve this problem, the effects of different slurry particle size distribution, initial moisture content of mud, pore diameter of geotextile, vacuum negative pressure and adding flocculant on the separation efficiency of mud water were studied, and the mechanism of plugging was discussed. It is found that the permeability coefficient of the mud skin formed by geotextile filtration will be the main factor restricting the dehydration effect. When the clogged mud skin is formed, the influence of other factors such as the pore size of the geotextile and the initial moisture content of the mud on the dehydration can be neglected. Adding flocculant can increase the permeability coefficient of mud crust, which is the reason for the better separation of mud water, and the smaller particle size of flocculant slurry determines the permeability coefficient of mud skin. Therefore, the optimum dosage of flocculant can be determined and the dehydration effect can be predicted by detecting the particle size of smaller aggregates such as D10, D15 and D20 in the slurry after flocculation. The addition of flocculant has little effect on the change of binding water content in mud, so it is considered that the change of water binding mode caused by flocculation does not affect the separation effect of mud water.
【作者单位】：河海大学岩土力学与堤坝工程教育部重点实验室;河海大学环境学院;
【基金】：国家重点基础研究发展计划(“973”计划)项目(2015CB057803) 国家科技重大专项(2013ZX07113001) 科技基础设施建设计划项目(BM2013013)
【分类号】：X703

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