基于含冰量的冻结砂土-混凝土接触面蠕变特性  

Creep Characteristics of Frozen Sand-Concrete Interface Based on Ice Content

作　　者：何菲[1] 王旭[1,2] 蒋代军[1] 周亚龙 李君善 陈航杰 陈明伟 HE Fei;WANG Xu;JIANG Daijun;ZHOU Yalong;LI Junshan;CHEN Hangjie;CHEN Mingwei(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;National and Provincial Joint Engineering Laboratory of Road&Bridge Disaster Prevention and Control,Lanzhou Jiaotong University,Lanzhou 730070,China;Maintenance Company,State Grid Qinghai Electric Power Company,Xining 810021,China)

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]兰州交通大学道桥工程灾害防治技术国家地方联合工程实验室,甘肃兰州730070 [3]国网青海省电力公司检修公司,青海西宁810021

出　　处：《西南交通大学学报》2024年第2期361-368,共8页Journal of Southwest Jiaotong University

基　　金：国家自然科学基金(41902272);甘肃省基础研究创新群体项目(21JR7RA347)。

摘　　要：保证高含冰量冻土区桩基础的长期稳定性是多年冻土区桥梁桩基础安全服役中的关键问题,为研究含冰量对冻土-混凝土接触面蠕变特性的影响,采用自行研制的大型蠕变剪切仪,在−2℃条件下开展含冰量为6%、12%、16%、23%、36%、60%、80%的冻结砂土与混凝土接触面蠕变试验.试验结果表明:在恒定的剪应力作用下,除含冰量为6%试样出现加速蠕变外,其他试样仅出现衰减蠕变及稳定蠕变2个阶段;随含冰量的增大,试样黏性变形占比增大,含冰量为80%试样的黏性变形超过总变形量的80%;稳定蠕变速率受到干密度及含冰量的综合影响,含冰量为16%时稳定蠕变速率最小;Burgers黏弹性模型能较好地模拟高含冰量冻结砂土-混凝土接触面蠕变曲线;随着含冰量的增大,初始剪切模量和稳定蠕变阶段黏滞系数先增大后减小,初始蠕变阶段的渐进剪切模量呈幂函数减小,初始蠕变阶段黏滞系数呈幂函数增大.Ensuring the long-term stability of the pile foundation in ice-rich frozen soil areas is the key to the safe use of bridge pile foundations in permafrost areas.In order to analyze the influence of ice content on the creep characteristics of the frozen sand-concrete interface,the creep tests of the frozen sand-concrete interface with ice content of 6%,12%,16%,23%,36%,60%,and 80%were carried out under−2℃by using self-designed large-scale shear apparatus.According to the test results,except for the accelerated creep of the specimen with 6%ice content,other specimens only experience decay creep and stable creep stages under constant shear stress.With the increase in ice content,the proportion of viscous deformation in the specimen increases,and the viscous deformation in the specimen with 80%ice content exceeds 80%of the total deformation.The stable creep speed is affected comprehensively by the dry density and ice content and is the lowest when the ice content is 16%.Burgers viscoelastic model can simulate the creep curve of frozen sand-concrete interface with high ice content better.With the increase in ice content,the initial shear modulus and viscosity coefficient at the stable creep stage increase first and decrease then.The progressive shear modulus at the initial creep stage decreases exponentially,and the viscosity coefficient at the initial creep stage increases exponentially.

关 键 词：高含冰量冻土 冻结砂土 接触面 蠕变试验 黏弹性模型 

分 类 号：TU445[建筑科学—岩土工程]