饱和粉土冻胀过程试验研究及数值模拟  

Experimental study and numerical simulation to the process of frost heave in saturated silt

作　　者：周家作[1] 韦昌富[1] 李东庆[2] 魏厚振[1] 裴万胜[2] 

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点试验室,湖北武汉430071 [2]中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室,甘肃兰州730000

出　　处：《岩石力学与工程学报》2017年第2期485-495,共11页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点基础研究计划(973)项目(2012CB026102);国家自然科学基金资助项目(41572293);中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室开放基金(SKLFSE201502)~~

摘　　要：为了研究温度梯度、冻结速率、土样高度和竖向压力对冻胀的综合影响,在不同试验条件下对饱和粉土进行了一系列一维土柱冻胀试验,试验中测量土样温度、竖向压力、冻胀量和补水量。试验结果表明:在温度场处于准稳态时,冻胀速率与温度梯度成正比例增长关系,冻胀速率随着竖向压力增大而线性减小;定义比冻结速率为冻结速率与土样高度之比,当温度场处于瞬态时,冻胀速率随比冻结速率成幂函数增长,增长率随着比冻结速率增大而减小。提出了综合考虑温度梯度、冻结速率、竖向压力和土样高度的冻胀计算公式,在此基础上推导了考虑水分迁移的冻土热扩散方程,提出了模拟冻胀和温度变化的数值模拟方法,通过一个数值算例计算了冻结过程中的温度和冻胀量变化,并与实测结果对比验证了该方法的可靠性。A series of experiments on frost heaving of 1D saturated silt columns were conducted under the different experimental conditions to comprehensively investigate the influence of temperature gradients,freezing rate,height of sample and vertical load on frost heaving. The temperature of samples,the vertical load,and the amount of frost heaving and the water intake were measured during each experiment. The experimental results show that when the temperature is quasi-steady,the frost heaving rate increases proportionally with the temperature gradient and decreases linearly with the vertical load. The specific freezing rate was defined as the ratio of freezing rate to the height of sample. When the temperature is unsteady,the frost heaving rate increases with the specific freezing rate in the form of power law and the rate of increasing decreases as the specific freezing rate increases. A formula for calculating the frost heaving was presented upon the comprehensively consideration of the temperature gradient,freezing rate,vertical load and height of sample. The thermal diffusion equationconsidering the water migration in frozen soil was deduced on the basis of the formula of frost heaving and the numerically solution was presented. The numerical results of the variation of temperature and frost heaving were compared with the experimental data,which confirmed the reliability of the simulating method.

关 键 词：土力学 饱和粉土 冻胀速率 温度梯度 竖向压力 比冻结速率 

分 类 号：TU445[建筑科学—岩土工程]