Thermo-hydraulic analysis of desiccation cracked soil strata considering ground temperature and moisture dynamics under the influence of soil-atmosphere interactions

Abstract

Global warming and climate change significantly affect ground temperature and flow patterns. Moreover, areas prone to cracking experience intensified temperature and moisture variations. Therefore, the aim of this study is to investigate ground temperature and moisture dynamics considering soil-atmosphere interaction through a coupled thermo-hydraulic analysis. Heat transfer, advective, and non-advective fluxes were simulated using CODE_BRIGHT finite element program to study water flow and energy transfer within the soil. Statistical analyses were conducted using an existing dataset to match the crack geometry with previous studies and find the best distribution for the width-to-depth ratio of cracks ($C_R$) as a dimensionless parameter. The results indicated that $C_R$ variations follow a lognormal distribution. Numerical modeling scenarios were developed using statistical analysis results. The findings indicate that temperature variations decrease exponentially with depth, while surface soil temperature shows higher uncertainty due to atmospheric temperature fluctuations. Collecting various temperature trends in cracked soil at different time intervals, defined a limited region as the maximum range of temperature variations ($∆T$). Results reveal that $∆T$ in cracked soil can vary up to 4 times higher than intact soil. For the prediction of $∆T$, considering the impact of climate variations on cracked soil, a 3D boundary surface was developed based on two variables: soil depth ($z$) and crack depth ($C_D$). Furthermore, an equation for estimating $∆T$ for uncracked soils was proposed. Additionally, cracked soil showed approximately 1.4 times higher desiccation rates than uncracked soil. Deeper cracks exhibited even more severe desiccation rates, being about 1.2 times higher.