饱和正冻土水热力耦合模型的改进  

Improvement of coupled thermo-hydro-mechanical model for saturated freezing soil

作　　者：何敏[1,2] 冯孝鹏 李宁[1] 刘乃飞[1] HE Min;FENG Xiao-peng;LI Ning;LIU Nai-fei(Institute of Geotechnical Engineering,Xi＇an University of Technology,Xi＇an 710048,China;Xibei Engineering Corporation Limited of Power Construction Corporation of China,Xi＇an 710065,China)

机构地区：[1]西安理工大学岩土工程研究所,陕西西安710048 [2]中国电建集团西北勘测设计研究院有限公司,陕西西安710065

出　　处：《岩土工程学报》2018年第7期1212-1220,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51179153);陕西省教育厅专项科研计划项目(17JK0557);陕西省“三秦学者”岩土工程(黄土工程特性研究)创新团队支持计划项目

摘　　要：在深入剖析已建立的饱和正冻土水热力耦合模型不足的基础上,结合冻土力学最新研究成果,基于连续介质力学和热力学定律对原模型进行改进以提高其实用性。首先,引入由冻融过程中的动态变量（应变速率）与温变速率构成的黏弹性耗散势,建立了考虑温度影响的冻土骨架的黏弹性本构关系;在此基础上根据多孔多相介质理论,建立了外载及温度共同作用下冻土骨架的质量守恒方程;其次,在考虑冻土骨架（冰）黏弹性耗散和热力耦合耗散以及水分迁移引起的热对流等主要因素的基础上建立了能量守恒方程;最后,综合各方程构建了准饱和正冻土水热力三场耦合控制微分方程,开发了相应的扩展有限元程序3GEXFEM,通过典型室内试验验证了改进后模型的合理性。Aiming at the shortcomings of the coupled thermo-hydro-mechanical model for saturated freezing soil, which employs a simplified linear elasticity constitutive relation, the assumption of complete saturation and the energy conservation based on conduction, a model is proposed by introducing the latest achievements of frozen soil. Firstly, the viscoelastic dissipation potential constituted by the strain rate and temperature rate is introduced, and a viscoelastic constitutive model that can consider the environmental effects of temperature is established. Then based on the theory of multiphase porous media, the mass conservation equation of frozen soil is established under the combination of load and temperature. By considering the main factors of the viscoelastic dissipation potential of frozen soil such as heat-mechanical coupling dissipation potential and thermal convection caused by water migration, the energy conservation equation is established. Finally, the governing differential equation is formulated by combination of the above equations, and the accuracy of the equation is verified by a classical laboratory test. It is shown that the results of the proposed model are well adapted for practical engineering.

关 键 词：饱和正冻土 耦合模型 黏弹性本构 对流传热 

分 类 号：TU47[建筑科学—结构工程]