冻融过程中冰水相变对非饱和粉土动力学性能的影响  

Effect of ice-water phase change on the dynamic properties of unsaturated silt during freeze-thaw process

作　　者：张玉芝[1,2,3] 王玺 王盟 王建州 梁少杰[4] 潘晓天 ZHANG Yuzhi;WANG Xi;WANG Meng;WANG Jianzhou;LIANG Shaojie;PAN Xiaotian(Key Laboratory for Health Monitoring and Control of Large Structures in Hebei Province,Shijiazhuang Tiedao University,Shijiazhuang,Hebei 050043,China;Collaborative Innovation Center for Performance and Safety of Large-scale Infrastructure,Shijiazhuang Tiedao University,Shijiazhuang,Hebei 050043,China;State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221008,China;School of Civil Engineering,Shijiazhuang Tiedao University,Shijiazhuang,Hebei 050043,China)

机构地区：[1]石家庄铁道大学河北省大型结构健康诊断与控制重点实验室,河北石家庄050043 [2]石家庄铁道大学大型基础设施性能与安全省部共建协同创新中心,河北石家庄050043 [3]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221008 [4]石家庄铁道大学土木工程学院,河北石家庄050043

出　　处：《岩石力学与工程学报》2024年第7期1799-1808,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金面上项目(52078312);中国矿业大学深部岩土力学与地下工程国家重点实验室开放课题(SKLGDUEK2104)。

摘　　要：冻融过程中,温度引起未冻水含量和含冰量的变化,进而影响冻融期间土体动力性能。基于此,采用朔黄重载铁路路基细粒填料——非饱和粉土,结合列车实际运营情况,开展冻结和融化过程中,不同初始含水率(10%,14%,18%)试样的核磁共振与温控动三轴试验,分析冻融过程中非饱和粉土未冻水质量含水率、含冰量与动弹性模量的关系,尝试探究土中冰水相变对宏观动力学特性的影响。主要结论如下:(1)降温过程中,从冻结温度降温至过冷温度过程中,未冻水含量大幅减少,含冰量和动弹性模量快速增加;之后随着温度持续降低,未冻水含量缓慢降低,含冰量和动弹性模量缓慢增加;继续降温至-15℃的过程中,发生相变的水分有限,且最终均有1%左右的液态水存在;(2)土体处于融化状态时,由于自由水的润滑作用,试样动弹性模量随初始含水率升高而降低;土体处于冻结状态时,由于冰胶结力作用,且冰在试样中的赋存状态不同,导致初始含水率14%试样冻结后的动弹性模量最大,初始含水率10%试样次之,初始含水率18%试样最小;(3)3组试样在冻融过程中均体现出动弹性模量与未冻水含量成反比、与含冰量成正比的规律。During the process of freezing and thawing,temperature-induced changes in the content of unfrozen water and ice affect the dynamic properties of the soil.Based on this,taking into account the actual operation conditions of trains,this study employed unsaturated silt,a fine-grained filler commonly used in the subgrade of the Shuozhou-Huanghua Port Heavy-Haul Railway,and conducted nuclear magnetic resonance(NMR)and temperature-controlled dynamic triaxial tests on samples with different initial water contents(10%,14%,and 18%)during both freezing and thawing processes.The aim was to analyze the relationships of the unfrozen water content and ice content with dynamic elastic modulus of unsaturated silt during freezing and thawing,thus to explore the impact of phase changes between ice and water on macro-dynamic properties.The main conclusions are as follows.(1)During the freezing process,from the freezing temperature to the supercooling temperature,the unfrozen water content decreases significantly,while the ice content and dynamic elastic modulus increase rapidly.Subsequently,as the temperature continue to drop,the unfrozen water content decrease slowly,and the ice content and dynamic elastic modulus increase gradually.Limited water phase changes occur during the subsequent freezing to-15℃,and approximately 1%of liquid water remains in all samples.(2)When the soil is in a thawed state,due to the lubricating effect of free water,the dynamic elastic modulus decrease as the initial water content increases.In the frozen state,the dynamic elastic modulus of the sample with an initial water content of 14%is the highest due to the ice cementation effect and the different modes of ice distribution within the sample.The dynamic elastic modulus of the sample with an initial moisture content of 10%is slightly lower,while the sample with an initial water content of 18%exhibit the lowest dynamic elastic modulus.(3)All three groups of samples exhibit an inverse relationship between the dynamic elastic modulus and the unfrozen wa

关 键 词：土力学 核磁共振 温控动三轴 未冻水 含冰量 动弹性模量 

分 类 号：TU43[建筑科学—岩土工程]