Study on Varying Characteristics of Temperature Field and Moisture Field of Shallow Loess in the Freeze‐Thaw Period

Zhang, Hui; Zhi, Bin; Liu, Enlong; Wang, Tiehang

doi:10.1155/2020/1690406

Cited by 5 publications

(2 citation statements)

References 23 publications

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“…Temperature change is an important factor leading to soil moisture phase changes and soil-water potential changes (Horel et al, 2022), and it is a major driver affecting the soil moisture movement in the soil freeze-thaw cycle (Wang et al, 2018). Soil temperature and air temperature have a synchronous change pattern under the freeze-thaw action (Zhang et al, 2020a;Chou and Wang, 2021). External environmental changes have had a greater impact on surface soil water content.…”

Section: Introductionmentioning

confidence: 99%

Effect of the interlayer on soil temperature and the transformation between phreatic water and soil water under laboratory freeze-thaw action

et al. 2023

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To reveal the effect of interlayer on the temperature of freeze-thaw soil and the transformation between phreatic water and soil water in shallow groundwater areas, a freeze-thaw test was conducted with a groundwater table depth of 0.5 m under laboratory freeze-thaw action. The soil temperature and the transformation between phreatic water and soil water of sand columns under constant freezing temperature at −20°C lasted for 20 days, and the thawing process lasted for 15 days were monitored. The interlayers with a particle size of 0.1–0.5 mm (d50 = 0.3 mm) and a thickness of 5 cm were set at 5, 15, 20, and 25 cm away from the surface and these sand columns were marked as D5, D15, D20, and D25, which were compared with a homogeneous sand column (Ch) with a particle size of 0.5–1.5 mm (d50 = 1.0 mm). The results showed that the fine particle interlayer had thermal insulation on the soil profile and that it effectively inhibited upward migration of phreatic water to soil water during the freezing process. A sand column that had a near-surface interlayer had a better thermal insulation, a stronger inhibition effect on upward migration amount of phreatic water to soil water (UMA) and a larger cumulative downward movement amount of soil water to phreatic water (DMA). The cumulative UMA of D5, D15, D20, and D25 was 61%–84% of Ch during the freezing stage, and the cumulative DMA of D5, D15, D20, and D25 was 29%–57% of Ch during the thawing stage. The inefficient loss of groundwater increased exponentially with the depth of interlayer, the sand column with an interlayer that was farther away from the surface consumed more groundwater and stored more water in the unsaturated zone, and its DMA reached almost zero earlier. These research results were significant for the scientific evaluation of water resources in shallow groundwater areas.

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Section: Introductionmentioning

confidence: 99%

Effect of the interlayer on soil temperature and the transformation between phreatic water and soil water under laboratory freeze-thaw action

et al. 2023

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“…However, due to the unique plastic deformation of steel, a delay (lag) between the maximum stress and plastic deformation may occur. For the study of stress accumulation in buried pipelines, some scholars have carried out numerical analyses of water-heat coupling (Kang et al, 2016;Zhang et al, 2020a, Zhang et al, 2021 and stress field calculation (Wen et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Pipeline Stress Test Simulation Under Freeze-Thaw Cycling via the XGBoost-Based Prediction Model

Teng

et al. 2022

Front. Earth Sci.

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This study conducted ten freeze-thaw cyclic tests to clarify the effect of freeze-thaw cycles on the forces acting on the buried oil pipeline. The stress evolution in the Q345 steel pipeline versus the number of freeze-thaw cycles was obtained. The test results were consistent with the COMSOL simulation of the effect of different moisture contents on the pipeline bottom stress. Besides the proposed XGBoost model, eleven machine-learning stress prediction models were also applied to 10–20 freeze-thaw cycling tests. The results showed that during the freeze-thaw process, the compressive stress at the pipeline bottom did not exceed −69.785 MPa. After eight freeze-thaw cycles, the extreme value of the principal stress of -252.437MPa, i.e., 73.17% of the yield stress, was reached. When the initial moisture content exceeded 20%, the eighth freeze-thaw cycle’s pipeline stress decreased remarkably. The XGBoost model effectively predicted the pipeline’s principal stress in each cycle of 10 freeze-thaw cyclic tests, with R2 = 0.978, MSE = 0.021, and MAE = 0.102. The above compressive stress fluctuated from −131.226 to −224.105 MPa. The predicted values well matched the experimental ones, being in concert with the “ratcheting effect” predicted by the freeze-thaw cycle theory. The results obtained provide references for the design, operation, and maintenance of buried oil pipelines.

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Mathematical Modeling of Seepage–Temperature Field for Earth Dam Using Experimental Test

Wang,

Gu,

Wang

et al. 2023

Mathematical Problems in Engineering

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Monitoring the seepage field is essential to characterize the operation of the earth dam. However, conventional seepage monitoring typically involves the use of a piezometer tube or pressure sensor for point distribution. A mathematical model incorporating the feedback of the temperature field on the seepage field was proposed based on experimental test observations. First, a theoretical analysis of the mathematical model is conducted, which includes examining the relationship between the variation of temperature field and factors, such as hydraulic gradient, water and soil temperature difference, hydraulic conductivity, thermal conductivity, specific heat, and time. Second, a homogeneous earth dam model is constructed in the laboratory with a distributed temperature sensor system to obtain synchronous information of the seepage–temperature field. Finally, the parameters of the mathematical model are quantified using observations from experimental tests, demonstrating good agreement between calculated and measured values. The experimental results indicate the feasibility of inferring seepage field monitoring information from the temperature field and elucidation of the interaction mechanism of the coupled fields. The quantitative mathematical model of the temperature field feedback on the seepage field is validated for its applicability in earth dams.

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Study on Varying Characteristics of Temperature Field and Moisture Field of Shallow Loess in the Freeze‐Thaw Period

Cited by 5 publications

References 23 publications

Effect of the interlayer on soil temperature and the transformation between phreatic water and soil water under laboratory freeze-thaw action

Effect of the interlayer on soil temperature and the transformation between phreatic water and soil water under laboratory freeze-thaw action

Pipeline Stress Test Simulation Under Freeze-Thaw Cycling via the XGBoost-Based Prediction Model

Mathematical Modeling of Seepage–Temperature Field for Earth Dam Using Experimental Test

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