Consolidation and strength characteristics of Ariake soft clay

本文介绍了有明湾沿海滩涂发育过程中粘粒的沉降、絮凝特性和浆化粘粒的自重固结特性，以及粘粒固结和边坡失稳的有关问题，有明粘粒在盐浓度大于0.1g/l时发生絮凝，发生絮凝时粘土的最大zeta电位为-20mV。絮凝沉降、界面沉降和压缩沉降分别发生在初始含水量高于5000%、5000 ~ 1000%和低于1000%时。本文还提出了不同厚度粘土的圆柱体自重固结试验方法，通过对粘土固结过程的研究，证实了次固结在固结度达到90%左右时开始，次固结的固结度与时间的对数比例在98%以上，并给出了强度和变形分析所需的参数。对有明粘土的化学性质进行了研究，结果表明，有明粘土中黄铁矿氧化产生的硫酸和氧化铁使粘土的pH值降低到4以下，从而释放出吸附在粘土表面的锌，导致地下水污染的潜在风险。

The present paper describes the settling and flocculation characteristics of clay particles and the self-weight consolidation characteristics of slurried clay associated with the development of tidal flat in Ariake Bay coastal area, and also the problems involved in the consolidation and slope failure of clays.Flocculation of Ariake clay occurs under the salt concentrations above 0.1g/1, and the maximum zeta potential of the clays when the flocculation occurs is -20mv. The flocculative, interface, and compression settlings occur at the initial water content of above 5000%, 5000 to 1000%, and below 1000%, respectively. The self-weight consolidation tests in cylinders for different clay layr thickness, is also proposed.The study of the consolidation of clays confirmed that the secondary consolidation started when the degree of consolidation reached to around 90%, and the degree of consolidation for secondary consolidation proportional to the time in logarithmic scale is above 98%.The parameters required for the strength and deformation analysis are presented, and the bearing capacity analysis for normally consolidated clay ground was performed under a partially drained condition.The investigation of the chemistry of Ariake clay indicated that the production of the sulfuric acid and iron oxide due to pyrite oxidation in the clays decreases pH below 4, which releases the adsorbed zinc on the clay surfaces, leading to the potential risk of groundwater contamination.