固结过程中天然沉积黏土结构性演化规律及机制研究  

Study on law and mechanism of structural evolution of natural sedimentary clay during consolidation

作　　者：朱楠 袁方龙 王健 ZHU Nan;YUAN Fang-long;WANG Jian(Tianjin Port Engineering Institute Co.,Ltd.of CCCC First Harbor Engineering Co.,Ltd.,Key Laboratory of Port Geotechnical Engineering of Ministry of Communications,Key Laboratory of Port Geotechnical Engineering of Tianjin,Tianjin 300222,China;CCCC First Harbor Engineering Co.,Ltd.,Tianjin 300461,China)

机构地区：[1]中交天津港湾工程研究院有限公司,港口岩土工程技术交通行业重点实验室,天津市港口岩土工程技术重点实验室,天津300222 [2]中交第一航务工程局有限公司,天津300461

出　　处：《中国港湾建设》2023年第4期15-21,共7页China Harbour Engineering

基　　金：中国交通建设集团有限公司科技研发项目(2021-207-03019)。

摘　　要：为了研究固结压缩过程中天然沉积黏土的结构性演化,开展原状土与重塑土的一维固结压缩和等向压缩试验。采用结构附加孔隙比Δe、应变结构性参数ms和割线模量结构性参数mE对土体结构性进行定量分析,并开展原状土微观结构试验揭示土体结构性演化的微观机制。通过研究得到:一维压缩条件下,土体结构性对刚度提高作用呈对数函数形式发展,分为增长阶段、过渡阶段、稳定阶段3个阶段。在等向压缩条件下,加载初期土体结构很快屈服破坏,之后结构性影响随应力增大近似呈线性发展。固结压缩过程中土体结构破损是渐进发展的,在土体结构屈服破坏后形成次生结构,结构性对刚度的影响逐渐稳定。天然沉积黏土的胶结连接和初始骨架结构为土体提供了额外刚度。在土体结构屈服破坏后胶结连接破坏,初始骨架结构破坏并重新调整形成新的次生结构,土体性质趋近于重塑土。In order to study the structural evolution of natural sedimentary clay during consolidation and compression,one-dimensional consolidation compression and isotropic compression tests of undisturbed and remolded soils were carried out.The structural additional void ratio Δe,strain structural parameter msand secant modulus structural parameter mEwere used for quantitative analysis of the soil structure,and the microstructure tests of undisturbed soil were carried out to reveal the microscopic mechanism of soil structure evolution.The results show that the effect of soil structure on the improvement of stiffness is logarithmic function under one-dimensional compression,which is divided into three stages including growth stage,transition stage and stability stage.Under the isotropic compression,the soil structure will yield quickly at the initial stage of loading,and then the effect of soil structure will develop linearly with the increase of stress.During the consolidation and compression of soils,the soil structure damage develops gradually,and a new structure is formed after the soil structure yields,with the influence of soil structure on the stiffness becoming gradually stable.Based on the microstructure analysis,the cementation and initial skeleton structure of natural sedimentary clay provides additional stiffness for soil.After the soil structure yields,the cementation is broken,and the initial skeleton structure fails and is changed to form a new structure with its mechanical properties tending to be that of remolded soil.

关 键 词：天然沉积黏土 固结压缩 应力应变特性 结构屈服应力 结构破损 

分 类 号：U655.54[交通运输工程—港口、海岸及近海工程] TU447[交通运输工程—船舶与海洋工程]