上海浅部黏土化学特性与沉积环境相关性

摘要

土体孔隙溶液化学特性反映其沉积环境,沉积环境影响土体的工程性质,其相关性是土力学的重要研究内容.本文首先详细介绍软土孔隙溶液化学特性的试验方法,并对上海浅层黏土展开试验研究.通过试验给出了土层各项化学特性指标的分布规律.结合上海地区海平面变化,探讨上海浅部土层的化学特性所反映的沉积环境变迁历史,尤其是第四纪海侵海退对土体化学特性的影响.分析土体的化学特性与其物理力学特性的相关性,获得了在不同沉积环境(海侵和海退)中软土的含盐量对灵敏度和物理指标的两种相反的影响规律.%The chemical properties of clay reflect its depositional environment and the depositional environment affects the engineering properties of clay.Their correlation is an important research content of soil mechanics.The test methods for the chemical properties of soft soil pore solution are introduced,and the tests on upper Shanghai clays are carried out.The distribution of each chemical properties index is given.Combined with the sea-level change in the Shanghai region,the history of changing depositional environment is reflected by the chemical properties of shallow Shanghai clays.Especially the Quaternary transgressive and regressive impact on chemical properties of clay is examined.The correlation between the chemical properties of Shanghai clays and their physical and mechanical properties is analyzed.Two opposite influences of salt content on sensitivity and physical parameters in different depositional environments(transgression and regression) are obtained.