考虑热效应的污染物在土中扩散、渗透和固结耦合模型  

Coupled model for contaminant diffusion,osmosis and consolidation in soil considering thermal effects

作　　者：田改垒 张志红[1] TIAN Gai-lei;ZHANG Zhi-hong(The Key Laboratory of Urban Security and Disaster Engineering,Ministry of Education,Beijing University of Technologyy,Beijing 100124,China)

机构地区：[1]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124

出　　处：《岩土工程学报》2022年第2期278-287,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金面上项目(51678012)。

摘　　要：为探究温度对污染物运移进程的影响,建立了考虑热效应的污染物在土中扩散、渗透和固结耦合模型,该模型不仅能够体现污染物运移过程中土体物理特性及输运性质的动态变化,同时实现了扩散、渗透和固结机制的耦合。在验证模型有效性的基础上,分析了热扩散、热渗透、热固结及其综合效应对污染物运移规律的影响。结果表明:热扩散、热渗透能够显著加快污染物运移,且随着索雷特系数和热渗透系数的增大,热扩散和热渗透效应对污染物运移的促进作用增强。而热固结效应则能够减缓污染物运移,但随着土体热膨胀系数的增加,垫层底部污染物积累质量浓度变化不大。当温差为40 K时,与不考虑热效应工况相比,考虑热扩散、热渗透和热固结综合效应影响下的污染物击穿时间缩短54 a。To explore the influences of temperature on pollutant transport,a coupled model for contaminant diffusion in soils,osmosis and consolidation considering the thermal effects is proposed to reflect the dynamic changes of physical properties of soils and transport properties in the process of pollutant transport and realize the coupling of diffusion,osmosis and consolidation.On the basis of verifying the validity of the model,the effects of thermal diffusion,thermo-osmosis,thermal consolidation and their combined effect on pollutant transport are analyzed.The simulated results show that the thermal diffusion and thermo-osmosis can accelerate contaminant transport,and with the increase of Soret coefficient and thermal permeability,the thermal diffusion and thermo-osmosis effects enhance.However,the thermal consolidation can slow down the pollutant transport rate,but with the increase of expansion coefficient of soils,the accumulation concentration of pollutant at the bottom of clay layer has little change.When the temperature difference is 40 K,the breakthrough time with considering the combined effects of thermal diffusion,thermo-osmosis and thermal consolidation can be shortened by 53.97 years compared with the results without considering the thermal effects.

关 键 词：热扩散 热渗透 热固结 污染物运移 

分 类 号：TU431[建筑科学—岩土工程]