开放系统下饱和正冻土热质迁移的数值分析  

Numerical Analysis of Heat and Mass Transfers in Saturated Freezing Soil in an Open System

作　　者：周家作[1,2] 李东庆[1] 房建宏 徐安花 

机构地区：[1]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 [2]中国科学院研究生院,北京100049 [3]青海省交通科学研究所,青海西宁810008

出　　处：《冰川冻土》2011年第4期791-795,共5页Journal of Glaciology and Geocryology

基　　金：冻土工程国家重点实验室基金项目(SKLFSE-ZY-03);中国科学院西部行动计划(二期)项目(KZCX2-XB2-10);国家高技术研究发展计划(863计划)项目(2008AA11Z103);多年冻土地区公路建设与养护技术交通行业重点实验室青海研究观测基地开放基金项目(2011-4-1)资助

摘　　要：引入Heaviside阶梯函数和Z函数使得冻结区和未冻区的导水系数、导热系数、体积热容量和土水势可以用统一的公式表达,提出了开放系统下饱和土在冻结过程中热质迁移的数学模型.对一个侧面绝热的圆柱土样的热质迁移过程进行了计算机模拟,结果表明:温度变化速率、冻结速率和温度梯度随时间减小,在冻结锋面附件温度分布曲线有拐点,冻结区温度梯度略小于未冻区温度梯度.含水量增量沿着试样高度先减小再增大,在冻结速率很低的情况下含水量持续增大,易形成冰透镜体.A mathematical model of heat and mass transfers in saturated freezing soil in an open system is proposed. Upon introducing Heaviside step function and Z function, hydraulic conductivities, thermal conductivities, volumetric heat capacities and soil-water potential of frozen zone and unfrozen zone can be expressed in a unified formula, respectively. The process of heat and mass transfers in a cylindrical soil specimen with adiabatic side wall is simulated on computer. The result shows that the rate of temperature change, freezing rate and gradient of temperature decrease with time. In the temperature distribution curve there is an inflection point near the freezing front. The gradient of temperature in frozen zone is slightly lower than that in unfrozen zone. The increment of water content first increases and then decreases along with the height of the specimen. In the case of low freezing rate, the water content continues to increase and an ice lens is likely to form.

关 键 词：开放系统 饱和正冻土 热质迁移 阶梯函数 

分 类 号：P642.14[天文地球—工程地质学]