不同应力路径下天然沉积软土的应力应变特性  

Stress-strain characteristics of natural sedimentary soft soil under different stress paths

作　　者：朱楠 吕海军 刘天韵[1,2,3,4,5] 张晓晓 ZHU Nan;LU Hai-jun;LIU Tian-yun;ZHANG Xiao-xiao(Tianjin Port Engineering Institute Co.,Ltd.of CCCC First Harbor Engineering Co.,Ltd.,Tianjin 300222,China;CCCC First Harbor Engineering Co.,Ltd.,Tianjin 300461,China;Key Laboratory of Port Geotechnical Engineering,Ministry of Transport,PRC,Tianjin 300222,China;Key Laboratory of Port Geotechnical Engineering of Tianjin,Tianjin 300222,China;Key Laboratory of Geotechnical Engineering,CCCC,Tianjin 300222,China)

机构地区：[1]中交天津港湾工程研究院有限公司,天津300222 [2]中交第一航务工程局有限公司,天津300461 [3]港口岩土工程技术交通行业重点实验室,天津300222 [4]天津市港口岩土工程技术重点实验室,天津300222 [5]中交集团岩土工程重点实验室,天津300222

出　　处：《中国港湾建设》2024年第10期51-57,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：为了揭示应力路径对天然沉积软土应力应变特性的影响,对原状天津软土和衡水湖软土开展物理力学指标、颗粒分析、常规三轴和应力路径三轴试验,系统研究了不同应力路径下天然沉积软土的应力应变特征及其影响因素,得到以下主要结论:结构性和胶结特性改变软土的应力应变特征,排水剪切下结构性和胶结特性较弱的天津软土表现出近似重塑土的应变硬化特征,而结构性和胶结特性较强的衡水湖软土表现出原状土典型的应变软化特征;天然沉积软土具有结构性和胶结特性,可承担一定的拉应力并产生膨胀变形;衡水湖软土黏粒和胶粒含量较高具有明显的胶结特性,在轴向卸载路径下抗剪强度更高且膨胀变形更大。研究结论可为天然沉积软土的设计计算和本构模型研究提供借鉴参考。In order to reveal the influence of stress paths on the stress-strain characteristics of natural sedimentary soft soil,physical and mechanical properties,conventional triaxial and stress path tests were carried out on the undisturbed soft soils of Tianjin and Hengshui Lake.The systematical investigation was conducted on the stress-strain characteristics and influencing factors of natural sedimentary soft soil under different stress paths.The main conclusions are as follows:stress-strain characteristics of soft soil are changed by the variation of the structural and bonding characteristics.Under the drainage shear,Tianjin soft soil with weaker structural and bonding characteristics reveals the strain hardening characteristics similar to remolded soil,while Hengshui Lake soft soil with stronger structural and bonding characteristics exhibits the strain softening characteristics of undisturbed soil.Due to the presence of structural and bonding characteristics,natural sedimentary soft soil can bear tensile stress and show expansion deformation.The content of clay particles and colloidal particles of Hengshui Lake soft soil are higher than Tianjin soft soil,exhibiting obvious bonding characteristics,higher shear strength and more significant expansion deformation under the axial unloading stress paths.The conclusions can provide reference for the design calculation and constitutive model of natural sedimentary soft soil.

关 键 词：天然沉积软土 三轴试验 应力路径 应力应变特性 

分 类 号：U652.21[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]