Influences of water phase change/migration factors in hydro-thermal coupling model for unsaturated soils

ZENG Zhao-jun; TANG Chao-sheng; CHENG Qing; AN Ni; SHI Bin

doi:10.11779/CJGE2022S1008

Volume 44 Issue S1

Turn off MathJax

Article Contents

Abstract

References

Chinese Journal of Geotechnical Engineering > 2022 > 44(S1): 40-45. > DOI: 10.11779/CJGE2022S1008

ZENG Zhao-jun, TANG Chao-sheng, CHENG Qing, AN Ni, SHI Bin. Influences of water phase change/migration factors in hydro-thermal coupling model for unsaturated soils[J]. Chinese Journal of Geotechnical Engineering, 2022, 44(S1): 40-45. DOI: 10.11779/CJGE2022S1008

Citation:

PDF (13908 KB)

Influences of water phase change/migration factors in hydro-thermal coupling model for unsaturated soils

1.
School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China
2.
College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China

More Information

Received Date: September 30, 2022
Available Online: February 06, 2023

Graphical Abstract

Abstract

Abstract

The numerical simulation is an important technique for investigating the coupled hydro-thermal behavior of unsaturated soils. In order to simplify calculation, the researchers often assume that water-vapor phase change is ignored during numerical study on the hydro-thermal behavior. To study the rationality of the hydro-thermal coupling problem of simplified calculation, based on the existing theory of hydro-thermal coupling model, which fully considers the coupling effects of heat conduction, water-vapor phase change, temperature gradient, moisture gradient and gravity, the FreeFem++-compiled hydro-thermal coupling model is used to study the application and evolution characteristics of the moisture and temperature fields. Based on the boundary conditions of groundwater level, surface evaporation, infiltration and wetting-drying in practical slope conditions, the rationality and coupling mechanism of factors such as latent heat, gravity, water vapor motion and permeability coefficient in the simplified calculation of coupled hydro-thermal problems are analyzed. The results show that, under the above boundary conditions, whether the latent heat is considered or not and the value of phase change coefficient significantly affect the distribution characteristics of the temperature field of soils, but the influences on the water migration are insignificant. In addition, the water migration of surface soil is faster, and water content is lower with the gravity considered and a larger permeability coefficient.
- unsaturated soil,
- hydro-thermal coupling model,
- atmosphere-soil interaction,
- gravity,
- water-vapor phase change

FullText(HTML)

References (11)

References

[1]	周扬, 周国庆. 土壤冻结水热耦合有限容积模拟研究[J]. 岩土工程学报, 2010, 32(3): 440–446. http://cge.nhri.cn/cn/article/id/12409 ZHOU Yang, ZHOU Guo-qing. Finite volume simulation for coupled moisture and heat transfer during soil freezing[J]. Chinese Journal of Geotechnical Engineering, 2010, 32(3): 440–446. (in Chinese) http://cge.nhri.cn/cn/article/id/12409
[2]	滕继东, 贺佐跃, 张升, 等. 非饱和土水气迁移与相变: 两类"锅盖效应"的发生机理及数值再现[J]. 岩土工程学报, 2016, 38(10): 1813–1821. doi: 10.11779/CJGE201610010 TENG Ji-dong, HE Zuo-yue, ZHANG Sheng, et al. Moisture transfer and phase change in unsaturated soils: physical mechanism and numerical model for two types of "canopy effect"[J]. Chinese Journal of Geotechnical Engineering, 2016, 38(10): 1813–1821. (in Chinese) doi: 10.11779/CJGE201610010
[3]	PHILIP J R, DE VRIES D A. Moisture movement in porous materials under temperature gradients[J]. Transactions, American Geophysical Union, 1957, 38(2): 222. doi: 10.1029/TR038i002p00222
[4]	LUIKOV A V. Heat and Mass Transfer in Capillary-Porous Bodies[M]. Oxford: Pergamon Press, 1966.
[5]	THOMAS H R. Modelling two-dimensional heat and moisture transfer in unsaturated soils, including gravity effects[J]. International Journal for Numerical and Analytical Methods in Geomechanics, 1985, 9(6): 573–588. doi: 10.1002/nag.1610090606
[6]	AN N, HEMMATI S, CUI Y J, et al. Numerical analysis of hydro-thermal behaviour of Rouen embankment under climate effect[J]. Computers and Geotechnics, 2018, 99: 137–148. doi: 10.1016/j.compgeo.2018.03.008
[7]	SELLERS P J, MINTZ Y, SUD Y C, et al. A simple biosphere model (SIB) for use within general circulation models[J]. Journal of the Atmospheric Sciences, 1986, 43(6): 505–531. doi: 10.1175/1520-0469(1986)043<0505:ASBMFU>2.0.CO;2
[8]	陈佩佩, 白冰. 内含圆柱域热源的非饱和土介质水热耦合作用的SPH数值模拟[J]. 岩土工程学报, 2015, 37(6): 1025–1030. doi: 10.11779/CJGE201506008 CHEN Pei-pei, BAI Bing. Numerical simulation of moisture-heat coupling in porous media with circular heat source by SPH method[J]. Chinese Journal of Geotechnical Engineering, 2015, 37(6): 1025–1030. (in Chinese) doi: 10.11779/CJGE201506008
[9]	SADAKA G. FreeFem++, a tool to solve PDEs numerically [M]. Arxiv, 2012: 1205, 1293.
[10]	van GENUCHTEN M T. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils[J]. Soil Science Society of America Journal, 1980, 44(5): 892–898. doi: 10.2136/sssaj1980.03615995004400050002x
[11]	CÔTÉ J, KONRAD J M. A generalized thermal conductivity model for soils and construction materials[J]. Canadian Geotechnical Journal, 2005, 42(2): 443–458. doi: 10.1139/t04-106