海洋环境下吹填钙质粉土夹层剪切特性研究  

Investigation on shear behavior of hydraulic fill calcareous silt interlayer in marine environment

作　　者：陈宾[1] 李圆程 张召 胡杰铭 CHEN Bin;LI Yuancheng;ZHANG Zhao;HU Jieming(College of Civil Engineering and Mechanics,Xiangtan University,Xiangtan 411105,China;School of Geosciences and Info-Physics,Central South University,Changsha 410083,China;College of Mechanics and Engineering Science,Hohai University,Nanjing 210098,China)

机构地区：[1]湘潭大学土木工程学院,湖南湘潭411105 [2]中南大学地球科学与信息物理学院,湖南长沙410083 [3]河海大学力学与工程科学学院,江苏南京210098

出　　处：《热带海洋学报》2024年第6期63-71,共9页Journal of Tropical Oceanography

基　　金：国家自然科学基金(42207227);湖南省自然科学基金(2022JJ40586);国家建设高水平大学公派研究生项目(202306710072)。

摘　　要：南海岛礁吹填工程建设中,建筑地基土层内易形成厚度不均、间断分布的钙质粉土夹层,目前关于钙质粉土夹层在高盐度海洋环境下的力学特性少有研究。本论文分别开展了不同水盐比下钙质粉土的直剪试验、激光粒度分析、Zeta电位分析和SEM试验。结果表明,钙质粉土的抗剪强度和内摩擦角随水盐比的增加呈先减后增的变化趋势,而黏聚力变化呈先增后减;当盐溶液进入过饱和阶段,土体抗剪强度和内摩擦角连续下降,而黏聚力单调升高。含盐量的升高可促进颗粒发生团聚,提高土颗粒表面电势,但随着含盐量进一步增加,颗粒团聚效应不再显著。进入过饱和阶段后,盐晶体沉淀析出,颗粒间胶结程度加强,并以“包裹”细颗粒的形式促进颗粒接触面的润滑作用。Calcareous silt interlayer with uneven thickness and disjunct distribution,is normally generated inside the building foundation during South China Sea Island reef reclamation project.Until now,investigation on the mechanical behavior of calcareous silt soils in the high-salt sea environment are scarcely carried out.In this paper,a series of direct shear tests,laser particle size analysis,Zeta potential analysis and SEM tests were performed to study the effects of water-salt ratio on shearing behaviors of calcareous silt soils.Experimental results demonstrated that the shear strength and internal friction angle of calcareous silt firstly decreased and then increased with the increase of water-salt ratio,but the cohesive force of soils showed an opposite pattern.When entering the supersaturation stage of salt content,the shear strength and internal friction angle continuously increased with increasing water-salt ratio,while the cohesive force monotonically decreased.Microstructural test results revealed that,the increase in salt content can improve the aggregation of silty soil particles and increase the particle surface potential,but this phenomenon becomes less significant at higher salt contents.After entering the supersaturation stage,salt crystals were formed inside the soils,which could improve the bonding degree between particles and promote lubrication of particle contact surfaces by wrapping fine particles.

关 键 词：钙质粉土 水盐比 剪切特性 粒度分析 Zeta电位分析 

分 类 号：P75[天文地球—海洋科学] TU44[建筑科学—岩土工程]