冻融循环条件下粗粒料变形特性试验研究  

Experimental study on deformation characteristics of coarse aggregates under freeze-thaw cycling conditions

作　　者：苏安双[1,2] 王宇 石北啸 李兆宇[2] 郑健 SU Anshuang;WANG Yu;SHI Beixiao;LI Zhaoyu;ZHENG Jian(State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Nanjing Hydraulic Research Institute,Nanjing 210029,China;Cold Region Engineering Research Institute,Heilongjiang Provincial Hydraulic Institute,Harbin 150080,China;Department of Geotechnical Engineering,Nanjing Hydraulic Research Institute,Nanjing 210029,China)

机构地区：[1]南京水利科学研究院水文水资源与水利工程科学国家重点实验室,江苏南京210029 [2]黑龙江省水利科学研究院寒区工程研究所,黑龙江哈尔滨150080 [3]南京水利科学研究院岩土工程研究所,江苏南京210029

出　　处：《河海大学学报（自然科学版）》2023年第6期61-66,共6页Journal of Hohai University(Natural Sciences)

基　　金：水文水资源与水利工程科学国家重点实验室开放研究基金项目(2020nkms07);冻土工程国家重点实验室开放基金项目(SKLFSE201920);水利部土石坝破坏机理与防控技术重点实验室开放基金项目(YK319003);国家重点研发计划项目(2017YFC0404801);黑龙江省自然科学基金联合引导项目(LH2019E124)。

摘　　要：为揭示粗粒料在冻融环境与复杂应力条件下的变形特性,采用大型三轴压缩试验与蠕变试验研究了粗粒料在不同冻融循环次数、围压与应力水平下的变形特性与蠕变特性。试验结果表明,未冻融粗粒料的应力应变曲线为应变硬化型曲线,在试验围压100~600 kPa范围内粗粒料剪切过程中均表现为剪胀性;冻融循环后初始弹性模量与破坏应力均呈下降趋势,200 kPa围压时,初始弹性模量降低20%,破坏应力降低37%,600 kPa围压时,初始弹性模量降低5%,破坏应力降低25%;冻融循环后粗粒料轴向蠕变应变随时间的发展为衰减型蠕变规律,轴向蠕变应变随冻融循环次数和应力水平的增大而逐渐增大,8次冻融循环后轴向蠕变应变明显增大;应力水平影响下的粗粒料蠕变时间曲线可采用指数函数形式表达。Based on the large-scale triaxial compression test and creep test of coarse aggregates under freezing and thawing environment,the deformation and creep characteristics of coarse aggregates under different freezing-thawing cycles,confining pressures and stress levels are studied.The test results show that the stress-strain relationship of unfrozen coarse-grained materials is a strain hardening curve,and the coarse-grained materials show dilatancy in the shear process within the confining pressure range of 100-600 kPa.Under the influence of freeze-thaw cycle,the initial elastic modulus and failure stress both show a downward trend.When the confining pressure is 200 kPa,the initial elastic modulus decreases by 20%and the failure stress decreases by 37%.When the confining pressure is 600kPa,the initial elastic modulus decreases by 5%and the failure stress decreases by 25%.The deformation of coarse-grained materials under freeze-thaw cycles develops into a decay-type creep with time.Meanwhile,the axial creep strain gradually increases with the increase of the number of freeze-thaw cycles and the stress level.The axial creep strain obviously increases after 8 freeze-thaw cycles and the creep time curve of coarse aggregates under the influence of stress level can be expressed in the form of exponential function.

关 键 词：粗粒料 冻融循环 变形特性 蠕变特性 

分 类 号：TV41[水利工程—水工结构工程]