海洋土颗粒分析试验分散剂使用研究

Application of dispersant in particle analysis tests of marine soil

在近海工程勘察中,由于海洋环境的特殊性和海洋土成因的复杂性,利用陆上土实践经验形成的密度计法进行颗粒分析试验时出现了测得的黏粒含量偏低,导致土的工程分类与野外定名相差较大的情况。本文通过对过筛(0.075mm)土悬液加入不同用量的浓度为4%的六偏磷酸钠后进行甲种密度计读数,将测得的黏粒、粉粒含量进行横向对比,以确定最佳分散剂用量,保证土悬液分散性的稳定,从而测得真实的黏粒含量。此外,还从海洋土的含盐度、矿物组成以及市场上销售的分散剂质量分析了出现上述问题的原因,并给出了海洋土颗粒分析试验中分散剂的使用建议。

In the offshore engineering survey,because of the particularity of marine environment and the complexity of marine soil origin,the clay content is low when using the densimeter method formed by the practical experience for land soil,which leads to the great difference between the engineering classification of soil and the eye recognition. In this paper, through adding different amount of 4% sodium hexametaphosphate into the sieved( 0. 075 mm) soil suspension,the readings of a densitometer are carried out,and the measured clay and silt content are compared with each other to determine the optimal dispersant dosage,to ensure the stability of the dispersion of the soil suspension and to measure the true clay content. In addition,the reasons for the above problems are analyzed from the salinity,mineral composition of marine soil and the quality of the dispersant sold in the market. Suggestions for the use of the dispersant in the particle analysis tests of marine soil are given.