海相软土场地水泥土劣化机理室内试验研究

将水泥土和周围土体作为研究对象,利用室内化学分析试验得到了离子浓度的时空分布规律,并从腐蚀离子干预水化反应进程和分解水化产物两个过程揭示了海相软土场地水泥土劣化机理。Ca^2+由水泥土向土体中扩散,Mg^2+、SO42^-及Cl^-从土体向水泥土扩散;随着水化反应的进行,Ca^2+不断生成,水泥土中足够多的Ca^2+是保证水化反应进行并维持水化产物稳定的必要条件,Ca^2+不断向土体扩散是水泥土劣化的原因之一;水泥土内部的SO42^-及Cl^-在浓度较低(分别低于9和15 g/L)时有利于水泥土强度的提高,浓度较高时则导致水泥土发生胀裂;水泥土中Mg^2+的存在会阻碍水化产物的生成并分解水化产物,但浓度较低(低于3 g/L)时,影响不明显;土体中Mg^2+、SO42^-及Cl^-浓度高于水泥土中的浓度,在水泥土表层与水化产物反应生成胶结性差及膨胀性高的物质,促使水泥土劣化。

Laboratory Study on Deterioration Mechanism of Cement Soil in Marine Clay Sites

In this paper, cement soil and surrounding soil were taken as the research object, and the spatial and temporal distribution law of ion concentration was obtained by using laboratory chemical analysis test, and the deterioration mechanism of cement soil in Marine clay site was revealed from the two processes of corrosion ion intervening hydration reaction process and decomposition hydration product diffused from cement soil to soil, while diffused from soil to cement soil. As the hydration reaction progressed, was constantly generated. Sufficient in cement soil is a necessary condition to ensure the hydration reaction and maintain the stability of hydration products. The continuous diffusion of to soil is one of the reasons for the deterioration of cement soil. The cement soil are beneficial to the strength of cement soil when the concentration is low, while the cement soil will swell and crack when the concentration is high. The presence of in cement soil can hinder the generation of hydration products and the decomposition of hydration products, but the effect is not obvious at low concentration. The concentration of 、 in soil is higher than that in cement soil, and they react with hydration products to produce substances with poor cementation and high expansion at cement soil surface, which promotes the deterioration of cement soil.