滨海软土剪切蠕变特性研究  

SHEAR CREEP PROPERTY AND CONSTITUTIVE MODEL FOR SOFT SOIL OF LITTORAL AREA IN TIANJIN

作　　者：雷华阳[1,2,3] 贾亚芳[2] 

机构地区：[1]天津市软土特性与工程环境重点实验室,天津300384 [2]天津大学土木工程系,天津300072 [3]天津大学滨海土木工程结构与安全教育部重点实验室,天津300072

出　　处：《工程地质学报》2013年第3期416-421,共6页Journal of Engineering Geology

基　　金：天津市软土特性与工程环境重点实验室开放基金项目(2011SCEEKL003);国家自然科学基金项目(51078262);国家重点基础研究发展计划(973)计划项目(2010CB732106)

摘　　要：为合理描述软土地区建筑物稳定性和运行安全性,采用剪切蠕变仪,开展了不同竖向荷载以及不同加荷比条件下滨海软土的剪切蠕变试验,获得不同条件下应变与应力和时间的关系,分析其剪切蠕变性状的结构性效应和影响因素,并最终建立了相应的本构方程。试验结果表明:应力大小明显影响天津滨海软土剪切蠕变性状,低应力下只出现衰减蠕变和稳定蠕变,高应力下会产生破坏型蠕变;低应力条件下应力-应变关系呈现出线性特性,高应力下呈现出非线性蠕变特性;采用较小的加荷比不仅可以减少最终蠕变量,还可以使软土承载力提高。根据蠕变曲线形态特征,建议一种指数函数型蠕变模型模拟天津滨海软土的非线性塑性蠕变特性。该模型具有简单易懂,参数较少,实用性较强的特点,通过对比分析,发现此蠕变模型能很好地拟合天津滨海软土的剪切蠕变特性。To describe the stability and operation safety of buildings on soft soil area, this article carries out a se- ries of shear creep tests of soft soil in Tianjin littoral area. Different vertical loads and load ratios are adopted in the shear creep instrument. It obtains the relationship of stain and stress and time in different conditions. It analyzes the structural effect and influence factors of the shear creep properties. It then establishes the corresponding consti- tutive model. The test results show that the shear creep properties of Tianjin littoral soft soil are obviously restricted by stress. The soil turns up attenuation creep and steady creep in low stress and destructive creep in high stress. The stress-strain presents a linear characteristics in lower stress and shows the nonlinear creep characteristics in higher stress, The smaller load ratio can not only reduce the final creep, but also improve the soft soil capacity. The nonlinear creep constitutive equation of Tianjin littoral soft soil is established with the theory of half experience and half theoretical method. The equation has the character of simple to understand, less parameters and strong practical. The model can well fit the Tianjin littoral soft soil creep characteristics through the compared analysis of experimental results and the creep model.

关 键 词：软土 剪切蠕变 非线性 指数函数 本构模型 

分 类 号：TU447[建筑科学—岩土工程]