非饱和正冻土的三场耦合理论框架

在``饱和正冻土的理论构架'的基础上，假定了冻土体内的空气的流动是一 种Darcy流，进一步考虑了非饱和土中气相的影响，提议了一种综合考虑两种极端 情况：(1) 气体与外界完全相通. (2) 气体与外界完全不相通的相关水、热、力相 耦合的多孔多相介质理论构架------半连通、半封闭非饱和正冻土理论构架. 重点讨论了较简单的气体半连通半封闭的非饱和孔隙冻土体的三场耦合模型. 为 检验三场耦合分析模型及所开发的针对冻土工程三场耦合模型的软件系统3G2001 的合理性与正确性, 与214国道花石峡 试验路基实测的地温变化和路基路面变形 进行了对比验证, 对比结果显示: 路基中分析所得的温度场与实测值变化规律一 致, 量化相差大都在10\%$\sim$20\%以内; 分析所得耦合变形随时间的变化也与 实测值完全一致, 路中的分析变形与实测相差也在10%-20%以内

Theoretical frame for unsaturated freezing soil

Soil freezing involves complex processes of a multi-phase porous medium and interactions with water, heat and deformation. The basic theoretical frame of the multi-phase porous medium is established in this paper in order to mathematically predict the complex freezing or thawing processes for cold region engineering problems. Based on the authors' theoretical frame work of the saturated freezing soil, this paper focuses on a four-phase unsaturated porous medium consisting of soil particle, ice, water and air. Further consideration of the air phase in the unsaturated freezing soil is discussed in this paper for two ideal situations: air in the soil is linked to the outside (the open porous medium), and air in the soil is sealed from the outside (the sealed porous medium). The corresponding theoretical frame work for a multi-phase porous medium with interaction of water, heat and deformation is proposed in this paper. The proposed theoretical model is then extended to the general case (unsaturated half-open and half-sealed porous medium), and a proper theoretical model for the heat-moisture-deformation coupling behavior of the unsaturated freezing soil is developed. And the software 3G2001 is also developed for the heat-moisture-deformation coupling behaviors. In-site measurements results for Hua Shixia highway roadbed are introduced to compare to the numerical results of the proposed model. The results indicate that numerical results of the temperature field variations along the roadbed depth at different time are with very good correlation to the measurements, and so do numerical results of the relatively freezing deformations of road surface. Both numerical accuracy to the measurements are within 10-20%. The comparison analysis shows the proposed theoretical frame and its numerical modeling for the temperature-moisture deformation coupling behaviors is suitable and acceptable.