摘要
为了研究季节冻土路基内部温度场、水分场及应力场综合效应的变化特性,基于自主研发的温度-湿度-荷载综合模型试验测试系统,进行室内路基模型的冻结与融化循环试验,分析了冻融循环过程路基内部土体水、热及力学性能的变化特性.试验表明:冻结过程中,初期温度变化大,温度梯度从顶端向底部逐渐递减;路基顶冻结后,0℃冻结锋面不断往下移动,0℃分界线两段内温度梯度差异大;路基含水率分为冻结区未冻水含量似稳定段、过渡区未冻水快速相变段、未冻结区含水率减小段.融化过程中,温度变化先大后小,未冻结水含量与温度大小相关,路基内部含水量呈现中间增大,两端减小的情形.水热综合作用下,应力场表现:冻融过程中,路基回弹模量随着冻结深度的增大呈线性增加,随融化深度的增加而减小;路基回弹模量随冻融循环次数增加而衰减,当达到6次时,衰减趋于稳定.结果表明,土体水热耦合作用是影响路基土体力学性能的关键因素.
In this paper,in order to study the variation characteristics of integrated effect of temperature field,moisture field and stress field on seasonally frozen soil inside subgrade,variation characteristics of hydrothermal and mechanical properties of soil inside subgrade during freeze-thaw cycle are analyzed from an experiment of freeze and thaw cycle on subgrade model in indoor,based on an independently developed test system for compositely modeling temperature-moisture-load.The results indicate that temperature variation is more at the beginning,with temperature gradient gradually decreasing from top to bottom;0 ℃ freezing front moves down continuously,and after subgrade top frozen,temperature gradient has great difference between the two segments upon and below the 0 ℃ separatrix;during the freezing process,water content in subgrade can be divided into frozen area with homo-stable unfrozen water,transition area with unfrozen water of fast phase change and unfrozen area with reducing moisture.During the thawing process,specimen has great temperature variation at first,and then becomes less and less;unfrozen water content is depend on temperature;water content is more in the middle and less in both ends.Under the composite effect of hydrothermal,the stress field is characterized by a resilient modulus of subgrade linearly increasing with frozen depth,but decreasing with thawed depth;resilient modulus of subgrade decreases with freeze-thaw cycles.When the cycles reach to 6,attenuation tends to be stable.The results show that coupling action of temperature and water is the key factor that controls the mechanical properties of soil in subgrade.
出处
《冰川冻土》
CSCD
北大核心
2012年第2期427-434,共8页
Journal of Glaciology and Geocryology
基金
国家自然科学基金项目(50708009)
交通部科技项目(200731822301-1)
2011年西藏自治区科技计划项目资助
关键词
温度场
湿度场
应力场
综合效应
冻融循环
temperature field
moisture field
stress field
composite effect
freeze-thaw cycles
作者简介
毛雪松（1976-），女，吉林春晖人，教授，2004年在长安大学获博士学位，现主要从事路基稳定性方面的教学与研究工作．Email：xuesongxian@yahoo．com．cn
