摘要
为研究不同冻融循环次数下黄河堤岸粉土应力-应变关系及抗剪强度的变化规律,开展了一系列三轴固结不排水剪切试验,并依据Kondner所提出的双曲线方程,对不同冻融循环次数后堤岸粉土的应力-应变关系曲线进行了归一化分析,考虑到不同围压及冻融循环次数对试样切线模量的影响,在数值上对模量损伤比进行了修正。结果表明:未冻融样的应力-应变关系曲线为应变硬化型,经不同次数冻融循环后变为应变稳定型,但在高围压下,试样的应力-应变曲线则出现弱软化特征,且随着冻融次数的增加,软化程度也随之增大;不同冻融循环次数下试样的抗剪强度,受粘聚力影响较大但受内摩擦角的影响较小,粘聚力最大降幅出现在土体第1次冻融循环之后。同时,基于三轴试验数据所建立的归一化方程能较好的预测不同冻融循环次数下试样的应力-应变关系,计算值与试验值较为接近。
In order to study the stress-strain relationship and shear strength of the embankment silt of Yellow River under different times freeze-thaw cycles,a series of triaxial consolidation undrained shear tests were carried out;according to the hyperbolic equation proposed by Konder,the stress-strain relationship curve of the embankment silt after different times of freeze-thaw cycles was normalized and analyzed,and considering the influence of different confining pressures and the time of freeze-thaw cycles on the tangent modulus of the silt sample,the modulus damage ratio was corrected.The results show that the stress-strain curve of the unfreeze-thaw silt sample is strain-hardening,and becomes strain-stable after different times of freeze-thaw cycles.However,under high confining pressure,the stress-strain curve of the silt sample shows weak softening characteristics,and as the time of freeze-thaw cycles increases,the degree of softening becomes more obvious;while the shear strength of the silt sample under different freeze-thaw cycles is greatly affected by the cohesive force but less affected by the internal friction angle,and the largest drop of the cohesive force occurs after the first freeze-thaw cycle of the silt.At the same time,the normalized equation established based on the triaxial test data can better predict the stress-strain relationship of the sample under different freeze-thaw cycles,and the calculated value is closer to the test value.
作者
石兆丰
牟献友
冀鸿兰
李超
杨震
张宝森
SHI Zhaofeng;MOU Xianyou;JI Honglan;LI Chao;YANG Zhen;ZHANG Baosen(College of Water Conservancy and Civil Engineering,Inner Mongolia Agricultural University,Hohhot 010018;The Yellow River Conservancy Commission,The Yellow River Water Conservancy Science Research Institute,Zhengzhou 450000,China)
出处
《干旱区资源与环境》
CSSCI
CSCD
北大核心
2021年第9期126-134,共9页
Journal of Arid Land Resources and Environment
基金
国家重点研发计划项目(2018YFC1508401)
国家自然科学基金项目(51969020,51569020,51969025)
2018自治区应用研究与开发资金项目(201802104)资助。
关键词
黄河堤岸粉土
冻融循环
应力-应变关系
抗剪强度
归一化
embankment silt of Yellow River
freeze-thaw cycles
stress-strain relationship
shear strength
normalization
