摘要
针对冻土热参数、土水势在不同温度条件下的变化趋势缺乏统一表述的问题,提出了冻土冻结势概念。为通过不同温度下的热参数和土水势变化率得到冻结势的表达式,首先,基于Johansen法反演不同温度下的冻土未冻水含量,根据未冻水含量计算出冻土热参数理论值,得出热参数在不同温度下的变化率;其次,通过土水特征曲线研究了冻土土水势随未冻水含量的变化关系,得出了冻土土水势在不同温度下的变化率;最后,根据以上计算结果拟合出了冻结势函数。研究结果表明:热参数及土水势在不同温度下产生不均匀变化的根本原因是未冻水含量的不均匀变化;随着土体温度的降低,未冻水含量、土水势、热参数先发生剧烈变化,随后变化趋势减缓并趋于某一数值;在温度为0^-5℃时,冻土冻结势急速发展,当温度低于-5℃时冻结势发展趋缓,由此得出0^-5℃是重塑冻土热参数和土水势性质的剧变区间。在此基础上,依据冻结势函数拟合出一种考虑温度变化的导热系数计算方法,该计算方法能较好地预测不同温度下冻土的导热系数。
The concept of frozen soil freezing potential was put forward in view of the lack of a unified estimating standard for the variation trend of the thermal parameters,soil-water potential of frozen soil at different temperatures.In order to obtain the expression of freezing potential according to the thermal parameters and the change rates of soil-water potential at different temperatures,firstly,based on the Johansen method,the unfrozen water contents of frozen soil at different temperatures were obtained,and the theoretical values of the thermal parameters of frozen soil were calculated through the unfrozen water contents,and the change rates of the thermal parameters at different temperatures were obtained;secondly,the relationship between the soil-water potential of frozen soil and the content of unfrozen water was studied by SWCC,and the change rates of soil-water potential of frozen soil at different temperatures were obtained;finally,the freezing potential function was fitted according to the above calculation results.The results showed that the fundamental reason for the variation of thermal parameter and soil-water potential at different temperatures was the variation of unfrozen water content;with the freezing temperature decreasing the content of unfrozen water in frozen soil,the water potential of frozen soil and the thermal parameters of frozen soil changed rapidly at first,then the change trend slowed down and tended to a certain value.When the freezing temperature was at 0℃to-5℃,the freezing potential of frozen soil varied rapidly,and when the freezing temperature was lower than-5℃,the freezing potential slowed down.From that,it was concluded that 0℃to-5℃was the sharp variable range of remolded frozen soil thermal parameters and soil-water potential properties.According to the freezing potential function,a method for calculating the thermal conductivity of frozen soil considering the change of freezing temperature was proposed,which could be used to predict the thermal conductivity of frozen soil at different temperatures.
作者
张翻
李顺群
夏锦红
刘烨璇
高凌霞
刘双菊
ZHANG Fan;LI Shunqun;XIA Jinhong;LIU Yexuan;GAO Lingxia;LIU Shuangju(School of Civil Engineering,Tianjin Chengjian University,Tianjin 300384,China;Tianjin Key Laboratory of Soft Soil Characteristics and Engineering Environment,Tianjin 300384,China;School of Civil Engineering and Architecture,Xinxiang University,Xinxiang 453003,China;College of Civil Engineering,Dalian Minzu University,Dalian 116600,China)
出处
《工业建筑》
CSCD
北大核心
2019年第7期97-101,82,共6页
Industrial Construction
基金
国家自然科学基金项目(41877251)
天津市自然科学基金重点项目(16JCZDJC39000)
天津市自然科学资金项目(15JCQNJC43700)
关键词
冻结势
冻土
土水势
土水特征曲线
热参数
未冻水
freezing potential
frozen soil
frozen soil-water potential
soil-water characteristic curve
thermal parameter
unfrozen water
作者简介
第一作者:张翻,男,1993年出生,硕士研究生;通信作者:李顺群,lishunqun@sina.com。
