钙离子浓度对泥沙淤积干容重影响试验研究

Experimental study on influence of Ca^(2+) concentration on the dry bulk density of sedimentation

通过静水沉降试验初步研究了天然河水中常见阳离子Ca2+对泥沙淤积干容重的影响。试验结果表明:①Ca2+浓度对泥沙淤积干容重的影响较大,随着Ca2+浓度增加,干容重的变化分为三个阶段:第一阶段干容重减小,第二阶段干容重增加并达到最大值,第三阶段Ca2+浓度继续增加后干容重减小最后趋于不变;②Ca2+浓度相同的情况下,泥沙浓度对干容重影响根据所加Ca2+浓度不同可分为三个阶段:第一阶段(Ca2+浓度在0~4mmol/l之间)随泥沙浓度增加干容重增加,第二阶段(Ca2+浓度在4~10mmol/l之间)干容重与各泥沙浓度在不同Ca2+浓度下的峰值有关,第三阶段(Ca2+浓度大于10mmol/l)干容重随泥沙浓度增加而增加;③Ca2+浓度、泥沙浓度相同时,中值粒径越大干容重越大,且中值粒径大的沙干容重达到最大值所需Ca2+少。

This paper studies the influence of Ca^2＋ concentration on the dry bulk density of sedimentation by settling experiments. The results show that ： （ 1 ） the influence of Ca^2＋concentration on the dry bulk density is obvious and the change of dry density with the increase of Ca^2＋ concentration can be divided into three phases, i.e. firstly decrease, then increase to the maximum, and finally maintain stable; （2） under the same Ca^2＋ concentration, the influence of sediment concentration on dry bulk density can also be divided into three phases, i.e. first the density increases with the sediment concentration if Ca^2＋ concentration is 0 - 4mmol/l, second the density is related to the maximum values of different Ca^2＋concentration when Ca^2＋ concentration is 4 - 10 mmol/l, and third the density increases with the sediment concentration under the Ca^2＋ concentration over 10 mmol/l; and （3） when Ca^2＋ concentration is equal to sediment concentration, the dry bulk density increases with sediment median size.