特殊应力路径下岸坡饱和土体变形特性模拟  

Deformation characteristics simulation of bank slope saturated soils under special stress paths

作　　者：陈勇[1,2] 杨迎[2] 曹玲[1,2] CHEN Yong YANG Ying CAO Ling(Collaborative Innovation Center for Geo-l-Iazards and Eco-Environment in Three Gorges Area, Hubei Province, Yichang, Hubei 443002, China College of Civil Engineering ＆ Architecture, China Three Gorges University, Yichang, Hubei 443002, China)

机构地区：[1]三峡地区地质灾害与生态环境湖北省协同创新中心,湖北宜昌443002 [2]三峡大学土木与建筑学院,湖北宜昌443002

出　　处：《岩土力学》2017年第3期672-677,684,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.51409149)~~

摘　　要：库岸边坡土体受到库水位涨落的周期性影响,其受力过程可描述为在前期固结压力范围内有效应力的多次循环加、卸载过程。通过室内应力路径三轴试验模拟土体孔隙水压力的循环加、卸载,并通过对统一硬化模型的扩展和加、卸载准则的修正,来预测土体的变形发展规律,研究结果表明:循环加、卸载过程中,土体的体积变形呈周期性弹性变化,剪应变呈螺旋上升趋势且增幅随循环次数逐渐减小;卸围压屈服阶段,土体变形呈现体积膨胀的剪胀特征和剪应变增幅加快的脆变趋势,且土体剪切变形在6%左右时即出现实测孔压骤减和峰值强度点;建立压缩曲线系数与加、卸载次数的关系,并修正超固结土的加、卸载准则,扩展后的统一硬化模型能够较好地预测特殊应力路径下岸坡饱和土体的变形特性。The bank slope soils are periodically influenced by the fluctuation of reservoir level, and its stress process can be described as multi-cyclic loading-unloading process of the effective stress in the pre-consolidation pressure range. The triaxial test of soil stress path is used to simulate the cyclic loading-unloading of soil pore water pressure, and the deformation and development laws of soil are predicted by extending the unified hardening model and modifying the loading-unloading criteria. The results show that during the cyclic loading-unloading process, the volume deformation of the soil is periodically elastic, and the shear strain is in a spiral upward trend and its increment gradually decreases with the number of cycles. During the unloading and confining pressure yielding stage, the soil deformation shows a dilatancy feature of volume expansion and a brittle trend of shear strain increase. The measured pore pressure drops dramatically and the peak intensity point occours when the shear deformation is at about 6%. The relationship between the compression curve coefficient and the number of loading-unloading is established, and the loading-unloading rules of the overconsolidated soil are modified. The extended unified hardening model can predict the deformation characteristics of the bank saturated soil under the special stress paths.

关 键 词：循环加卸载 应力路径 统一硬化模型 加卸载准则 

分 类 号：TV698.11[水利工程—水利水电工程]