含离子浓度参数的粘性泥沙沉速公式研究

以长江为例分析了河流中的水化学特性,得出河流中影响粘性泥沙沉速的主要是Ca2+。阳离子影响泥沙沉速的主要原因是粘性沙的絮凝。对泥沙絮凝沉降过程进行理论分析,推导出絮凝沉速与离子浓度之间的关系式。并且根据试验结果确定以Ca2+浓度为参数时经验关系式中的系数值。用实测的沉速对絮凝沉速公式进行了初步的验证。验证结果表明,用张瑞瑾沉速公式计算结果与实测结果相差很大,而絮凝沉速公式计算结果与实测结果相符合。

Study on the fine sediment settling velocity formula with the parameter of Ca2 + concentration

The ions in the nature river would affect the fine sediment settling velocity.But the sediment settling velocity formula could not reflect the influence before.So the formula could not compute the velocity of the sediment particle settling in the water with ions.It is necessary to amend the formula to compute the velocity in this situation.The fundamental cause of generating influence on the settling velocity by ions is flocculation of fine sediment.And in this process the most important ions in river are high valency cations.Based on the analysis of sediments flocculation process,a empirical formula between the settling velocity of the fine sediment flocculation and the ion concentration is established.And the emcpirical relationship based on the experimentations is given.So the coefficients in the formula are confirmed by the experience of the sediment settling velocity in the distilled water and the water with different Ca~(2 ) concentration.By taking account of the Zhang Ruijin formula and the empirical relationship formula,the sediment flocculation settling velocity formula about Ca~(2 ) comes into being.The preliminary verification of the formula is made through the contrast between the actual measured value and computed one.The results of verification show that the results computed by the flocculation settling velocity formula are more rigorous than those done by the Zhang Ruijin formula.