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1
Shiozawa, Sho, and Gaylon S. Campbell. "Soil thermal conductivity." Remote Sensing Reviews 5, no. 1 (1990): 301–10. http://dx.doi.org/10.1080/02757259009532137.
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Cui, Fu-Qing, Wei Zhang, Zhi-Yun Liu, et al. "Assessment for Thermal Conductivity of Frozen Soil Based on Nonlinear Regression and Support Vector Regression Methods." Advances in Civil Engineering 2020 (August 28, 2020): 1–12. http://dx.doi.org/10.1155/2020/8898126.
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The comprehensive understanding of the variation law of soil thermal conductivity is the prerequisite of design and construction of engineering applications in permafrost regions. Compared with the unfrozen soil, the specimen preparation and experimental procedures of frozen soil thermal conductivity testing are more complex and challengeable. In this work, considering for essentially multiphase and porous structural characteristic information reflection of unfrozen soil thermal conductivity, prediction models of frozen soil thermal conductivity using nonlinear regression and Support Vector Regression (SVR) methods have been developed. Thermal conductivity of multiple types of soil samples which are sampled from the Qinghai-Tibet Engineering Corridor (QTEC) are tested by the transient plane source (TPS) method. Correlations of thermal conductivity between unfrozen and frozen soil has been analyzed and recognized. Based on the measurement data of unfrozen soil thermal conductivity, the prediction models of frozen soil thermal conductivity for 7 typical soils in the QTEC are proposed. To further facilitate engineering applications, the prediction models of two soil categories (coarse and fine-grained soil) have also been proposed. The results demonstrate that, compared with nonideal prediction accuracy of using water content and dry density as the fitting parameter, the ternary fitting model has a higher thermal conductivity prediction accuracy for 7 types of frozen soils (more than 98% of the soil specimens’ relative error are within 20%). The SVR model can further improve the frozen soil thermal conductivity prediction accuracy and more than 98% of the soil specimens’ relative error are within 15%. For coarse and fine-grained soil categories, the above two models still have reliable prediction accuracy and determine coefficient (R2) ranges from 0.8 to 0.91, which validates the applicability for small sample soils. This study provides feasible prediction models for frozen soil thermal conductivity and guidelines of the thermal design and freeze-thaw damage prevention for engineering structures in cold regions.
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He, Ruixia, Ning Jia, Huijun Jin, Hongbo Wang, and Xinyu Li. "Experimental Study on Thermal Conductivity of Organic-Rich Soils under Thawed and Frozen States." Geofluids 2021 (September 23, 2021): 1–12. http://dx.doi.org/10.1155/2021/7566669.
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Thermal properties are important for featuring the water-heat transfer capacity of soil. They are also key to many processes in earth sciences, such as the land surface processes and ecological and geoenvironmental dynamics and their changes in permafrost regions. With loose and porous structures, the organic matter layer in soil strata substantially influences soil thermal conductivity. So far, thermal conductivity of mineral soils has been explored extensively and in depth, but there are only limited studies on that of organic soils. In this study, influences of soil temperature, soil moisture saturation (SMS), and soil organic matter (SOM) content on soil thermal conductivity were analyzed on the basis of laboratory experiments on the silt-organic soil mixtures of varied mixing ratios. Results show that soil thermal conductivity declines slowly with the lowering temperatures from 10 to 0°C; however, it increases and finally stabilizes when temperature further lowers from 0 to -10°C. It is important to note that thermal conductivity peaks in the temperature range of -2~0°C (silty and organic-poor soil) and -5~0°C (organic-rich soil), possibly due to phase changes of ice/water in warm permafrost. Under both thawed and frozen states, soil thermal conductivity is positively related with SMS. However, with rising SOM content, the growth rate of soil thermal conductivity with SMS slows gradually. Given the same SMS, soil thermal conductivity declines exponentially with increasing SOM content. Based on the experimental and theoretical analyses, a new empirical computational formula of soil thermal conductivity is established by taking into account of the SOM content, SMS, and soil temperature. The results may help better parameterize in simulating and predicting land surface processes and for optimizing frozen soil engineering designs and provide theoretical bases for exploring the dynamic mechanisms of environmental changes in cold regions under a changing climate.
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Sun, Qiang, and Chao Lü. "Semiempirical correlation between thermal conductivity and electrical resistivity for silt and silty clay soils." GEOPHYSICS 84, no. 3 (2019): MR99—MR105. http://dx.doi.org/10.1190/geo2018-0549.1.
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Previous researchers have shown that thermal conductivity and electrical resistivity are related to the water content and void ratio of soil. The objective of this study is to present a theoretical relationship between these two physical parameters. A de Vries equation and Archie’s law are applied to develop a new theoretical equation that relates thermal conductivity to the electrical resistivity of soil. The DRE-2C thermal conductivity tester, which uses a transient plane-source method, is used to measure the thermal conductivity. In addition, the DDC-8 resistivity meter is used to measure the electrical resistivity. Experiments on the thermal conductivity and electrical resistivity of silt soil and silty clay soil with different gravimetric water contents and densities are performed. The results indicate that the theoretical equation can well explain the relationship between the thermal conductivity and electrical resistivity of silt and silty clay soils. The thermal conductivity and electrical resistivity are also found to have a linear relationship with the density of silt soil. When the gravimetric water content is less than 30%, the thermal conductivity and electrical resistivity of silty clay soil increase linearly with the density. The thermal conductivity increases with the gravimetric water content to a critical threshold depending on the soil type. The silty clay samples with a water content of 20% have the largest value of thermal conductivity. The electrical resistivity of the silt and silty clay samples decreases rapidly due to the increased pore connectivity and enhanced hydration of ions in soil with the increased water content. The results of the experiments indicate that the new theoretical equation is effective for estimating the soil electrical resistivity from the soil thermal conductivity.
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Han, Qiang, Zhiguo Wang, and Rui Qin. "Thermal Conductivity Model Analysis of Unsaturated Ice-Containing Soil." Geofluids 2022 (July 12, 2022): 1–15. http://dx.doi.org/10.1155/2022/3717705.
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In cold locales, the thermal conductivity of soil porous media varies according to their composition and the phase state of the substance contained within the pore space. During the winter, water and other media in the soil pore space freeze-thaw, resulting in their phase state, composition, distribution, and significant thermal conductivity changes. There are some shortcomings in the current research regarding the thermal conductivity change pattern of unsaturated ice-containing soils. In this paper, the representative elementary volume (REV) selection method is given for unsaturated ice-containing soil with porosity as a representative state variable. Under the condition of freeze-thaw, two thermal conductivity REV analysis models for unsaturated ice-containing soil are established: a simplified volume-weighted average REV model and a fine volume-weighted average REV model; accordingly, a macroscopic thermal conductivity analysis model is given. The computational analysis is carried out with an actual unsaturated ice-containing soil example. The influence of the application of frozen soil in China is examined for its effect on the variation law of the thermal conductivity of porous medium. The variation characteristics of thermal conductivity of permafrost soil with related parameters (porosity, water ratio, moisture percentage, ice content, and tortuosity) are discussed. The model built in this paper provides novel concepts and methods for analyzing the thermal conductivity characteristics of unsaturated soil, as well as enhancing and advancing the analysis.
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Tarnawski, Vlodek R., and Bernhard Wagner. "A new computerized approach to estimating the thermal properties of unfrozen soils." Canadian Geotechnical Journal 29, no. 4 (1992): 714–20. http://dx.doi.org/10.1139/t92-079.
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Results from a user friendly, menu-driven, and interactive computer program for rapid estimation of thermal properties of soils are presented. The model developed is an extension of the de Vries approach. The new model allows easy estimation of the thermal conductivity of soils with approximately log-normal particle-size distribution. The model introduces the individual characteristics of five main mineral soil constituents (i.e., quartz, feldspar, calcite, clay minerals, and mica) and relates their occurrence in individual soils to grain-size distribution. The user also has a possibility of inserting to the model up to 20 additional mineralogical components, providing that mass fraction, thermal conductivity, density, shape, and specific heat are known. Soil-water hydraulic relations follow an extended power function model and allow the calculation of the apparent thermal conductivity of soils (water-vapor migration) at low moisture contents. Thus the model predicts soil thermal conductivity in a full range of moisture content from dryness to saturation and a temperature range of 0–95 °C. Good agreement with experimental data was reported. Key words : moist soils, soil thermal properties, thermal conductivity, specific heat, de Vries method.
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Ingersoll, J. G. "Analytical Determination of Soil Thermal Conductivity and Diffusivity." Journal of Solar Energy Engineering 110, no. 4 (1988): 306–12. http://dx.doi.org/10.1115/1.3268272.
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A simple model has been developed that can be used to calculate the soil thermal conductivity and diffusivity on the basis of the following factors: soil porosity; soil water content; conductivity, specific heat, and density of the constituents of soil, i.e., solid matter, water, and air. The model assumes that the void space in soil can be presented by a combination of plane fissures, whose direction is either parallel to the heat flow or perpendicular to it. A coefficient introduced to account for this combination in the two directions can be estimated from measured data as a function of the soil water content. Moreover, it is assumed that air and moisture conduct heat across the fissures in parallel. It is found that soil conductivity and diffusivity increase relatively rapidly with a few percent addition of moisture to entirely dry soil. For instance, assuming a typical soil porosity of 40 percent we conclude that the ratio of soil diffusivities of saturated to dry soil is about four, while that of soild with 2.5 percent moisture content to dry soil is a little over two. That is to say, a small moisture addition to dry soil brings the diffusivity half way to its saturation value. Since soil always contains small amounts of moisture, this finding explains the fact that measured seasonal temperature damping factors in extreme humid and extreme arid climates differ by less than a factor of two even though the moisture content of the respective soils may differ by more than an order of magnitude.
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Barry-Macaulay, D., A. Bouazza, B. Wang, and R. M. Singh. "Evaluation of soil thermal conductivity models." Canadian Geotechnical Journal 52, no. 11 (2015): 1892–900. http://dx.doi.org/10.1139/cgj-2014-0518.
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Numerous models have been developed to predict the thermal conductivity of soils at a range of different densities and moisture contents. This paper evaluates four thermal conductivity models, developed by various researchers, by comparing their performance against experimental results obtained on 27 different soils prepared at a range of saturation levels and densities. The results demonstrate that, in general, all four models show good agreement between experimental thermal conductivity and modelled thermal conductivity. The only significant shortfall is observed in low-saturated sands when using two of the models. A detailed analysis of the empirical soil parameters used in three of the recent models is presented. It shows that the accuracy of the three models can be improved by modifying the empirical soil parameters to fit the experimental data.
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Ross, PJ, and BJ Bridge. "Thermal properties of swelling clay soils." Soil Research 25, no. 1 (1987): 29. http://dx.doi.org/10.1071/sr9870029.
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The thermal properties of swelling clay soils do not appear to have been previously studied, even though they should be different from those of non-swelling soils because of changes in pore size and structure with water content. We measured the thermal diffusivity of small discs cut from cores of a highly swelling black earth (Pellustert) using the pulse method, common in materials science but not previously applied to soils. Thermal conductivity was calculated from thermal diffusivity and heat capacity per unit volume. The behaviour of these thermal properties was indeed different from those reported for nonswelling soils. The conductivity and diffusivity at low water contents were several times higher, increased much less with water content, and eventually decreased when the soil became saturated and swelled. The heat capacity per unit volume increased more slowly with water content because of the swelling. Over the agriculturally important suction range from 10 kPa to 1.5 MPa (0.1 to 15 bar), the conductivity decreased with increasing water content, a behaviour opposite to that of non-swelling soils. The behaviour could be predicted by three theoretical models, each with two parameters estimated from the data. The first parameter, the conductivity of soil solids, was common to all models, and estimated values ranged from 2.2 to 2.6 Wm-' K-l. The model of de Vries, commonly used in soil science, was applied with the soil solids matrix as the continuous medium and fitted the data particularly well. The second parameter in this model was a shape factor for small pores. Its estimated value corresponded with spheroidal pores with a diameter-to-height ratio of 16, which is reasonable in a swelling clay soil. The de Vries model was used to calculate the conductivity of bulk soil in the vertical direction, assuming that 20% of soil shrinkage appeared as isolated, randomly distributed cracks between aggregates. The conductivity was substantially less than that of the aggregates at lower water contents, but differed little for wetter soil at suctions below 1.5 MPa. In contrast, calculated values of conductivity were much lower when the de Vries model was applied with air as the continuous medium to a cultivated soil structure such as might be found in a seedbed.
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Muhudin, Abdullahi Abdulrahman, Mohammad Sharif Zami, Ismail Mohammad Budaiwi, and Ahmed Abd El Fattah. "Experimental Study of Thermal Conductivity in Soil Stabilization for Sustainable Construction Applications." Sustainability 16, no. 3 (2024): 946. http://dx.doi.org/10.3390/su16030946.
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Soils in Saudi Arabia are emerging as potential sustainable building materials, a notion central to this study. The research is crucial for advancing construction practices in arid areas by enhancing soil thermal properties through stabilization. Focusing on Hejaz region soils, the study evaluates the impact of stabilizers such as cement, lime, and cement kiln dust (CKD) on their thermal behavior. This investigation, using two specific soil types designated as Soil A and Soil B, varied the concentration of additives from 0% to 15% over a 12-week duration. Employing a TLS-100 for thermal measurements, it was found that Soil A, with a 12.5% cement concentration, showed a significant 164.54% increase in thermal conductivity. When treated with 2.5% lime, Soil A reached a thermal conductivity of 0.555 W/(m·K), whereas Soil B exhibited a 53.00% decrease under similar lime concentration, reflecting diverse soil responses. Notably, a 15% CKD application in Soil A led to an astounding 213.55% rise in thermal conductivity, with Soil B recording an 82.7% increase. The findings emphasize the substantial influence of soil stabilization in improving the thermal characteristics of Hejaz soils, especially with cement and CKD, and, to a varying extent. This study is pivotal in identifying precise, soil-specific stabilization methods in Saudi Arabia’s Hejaz region, essential for developing sustainable engineering applications and optimizing construction materials for better thermal efficiency.
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Laimech, Abderrahim, Feth-Ellah Mounir Derfouf, Khalfallah Mekaideche, and Nabil Aboubekr. "Influence of degree of saturation on the thermal conductivity of soils: Experimental and comparative model analysis." Journal of Engineering and Exact Sciences 10, no. 6 (2024): 19473. http://dx.doi.org/10.18540/jcecvl10iss6pp19473.
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The thermal conductivity can characterize thermal behaviour of soils in different engineering studies: environmental, geothermal, geotechnical and buildings construction. However, accurately measuring and predicting this parameter poses a challenging task. Measuring this parameter can be very complex, considering several factors, such as soil heterogeneity and external climatic conditions. In addition, predictions models may not capture all the nuances of real-world soil conditions, leading to less accurate predictions of ?. The objectives of this paper encompassed two primary aspects: (i) Evaluation of laboratory tests of thermal conductivity of unsaturated soil. (ii) Assessment of five highly recommended soil thermal conductivity models to determine their validity and strengthen their trustworthiness. The studied material consisted of calcareous tufa locally available in Beni-Saf region (Algeria). The tested samples were compacted to the Standard and Modified Proctor Optimum (SPO, MPO) followed by drying periods under laboratory conditions. The thermal conductivity of samples was evaluated using transient method. The models’ predictive results of the thermal conductivity were assessed with different criteria such as Mean Absolute Error (MAE), Root Mean Squared Error (RMSE), and Coefficient of Determination R². Furthermore, this work also attempts to deliver an in-depth discussion of the effect of degree of saturation Sr on the thermal conductivity of soils.
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Kodešová, R., M. Vlasáková, M. Fér, et al. "Thermal properties of representative soils of the Czech Republic." Soil and Water Research 8, No. 4 (2013): 141–50. http://dx.doi.org/10.17221/33/2013-swr.
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Knowledge of soil thermal properties is essential when assessing heat transport in soils. Thermal regime of soils is associated with many other soil processes (water evaporation and diffusion, plant transpiration, contaminants behaviour etc.). Knowledge of thermal properties is needed when assessing effectivity of energy gathering from soil profiles using horizontal ground heat exchangers, which is a topic of our research project. The study is focused on measuring of thermal properties (thermal conductivity and heat capacity) of representative soils of the Czech Republic. Measurements were performed on soil samples taken from the surface horizons of 13 representative soil types and from 4 soil substrates, and on mulch (bark chips) sample using KD2 PRO device with TR-1 and SH-1 sensors. The measured relationships between the thermal conductivity and volumetric soil-water content were described by the non-linear equations and those between the volumetric heat capacity and volumetric soil-water content were expressed using the linear equations. The highest thermal conductivities were measured in soils on quartz sand substrates. The lowest thermal conductivities were measured in the Stagnic Chernozem Siltic on marlite and the Dystric Cambisol on orthogneiss. The opposite trend was observed for maximal heat capacities, i.e. the highest values were measured in the Stagnic Chernozem Siltic and the lowest in sand and soils on sand and sandy gravel substrate.
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Glagolev, M. V., E. A. Dyukarev, I. E. Terentieva, and A. F. Sabrekov. "On a question of non-constant thermal diffusivity of soils." IOP Conference Series: Earth and Environmental Science 1093, no. 1 (2022): 012019. http://dx.doi.org/10.1088/1755-1315/1093/1/012019.
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Abstract The general heat conductivity equation includes time- and depth-dependent soil properties (soil heat capacity and thermal conductivity). The simplified form of the heat conductivity equation contains only the soil thermal diffusivity parameter. Numerical solutions of the general and simplified equations were compared to quantify the possibility of equation reduction. Two test runs for soils with different compositions were done. The thermal regime for both peat soil and dark chestnut soil does not change significantly after using a simplified heat equation according to model estimations. The maximal soil temperature discrepancy was about 0.5 °C for peat soil and 2.2-3.3 °C for dark chestnut soil, which results in 4-6% error in methane efflux estimations.
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Ren, Xiuling, Yanhui You, Qihao Yu, Guike Zhang, Pan Yue, and Mingyang Jin. "Determining the Thermal Conductivity of Clay during the Freezing Process by Artificial Neural Network." Advances in Materials Science and Engineering 2021 (March 26, 2021): 1–10. http://dx.doi.org/10.1155/2021/5555565.
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Thermal conductivity is an important thermal parameter in engineering design in cold regions. By measuring the thermal conductivity of clay using a transient hot-wire method in the laboratory, the influential factors of the thermal conductivity of soils during the freezing process were analyzed, and a predictive model of thermal conductivity was developed with an artificial neural network (ANN) technology. The results show that the variation of thermal conductivity can be divided into three stages with decreasing temperature, positive temperature stage, transition stage, and negative temperature stage. The thermal conductivity increases sharply in the transition stage. The difference between the thermal conductivity at positive and negative temperature is small when the dry density of the soil specimens is larger than the critical dry density, while the difference is large if the dry density is less than the critical dry density. As the negative temperature decreases, the larger the moisture content of the soil specimens, the larger the increase of thermal conductivity. The effect of initial moisture content on thermal conductivity is more significant than that of dry density and temperature. The change tendency of the thermal conductivity calculated by the established ANN model is basically consistent with that of the laboratory-measured values, indicating that this model can be able to accurately predict the thermal conductivity of the soil specimens in the freezing process.
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He, Hailong, Lanmin Liu, Miles Dyck, Bingcheng Si, and Jialong Lv. "Modelling dry soil thermal conductivity." Soil and Tillage Research 213 (September 2021): 105093. http://dx.doi.org/10.1016/j.still.2021.105093.
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Rerak, Monika. "Selected soil thermal conductivity models." E3S Web of Conferences 13 (2017): 02003. http://dx.doi.org/10.1051/e3sconf/20171302003.
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Côté, Jean, and Jean-Marie Konrad. "Indirect methods to assess the solid particle thermal conductivity of Quebec marine clays." Canadian Geotechnical Journal 44, no. 9 (2007): 1117–27. http://dx.doi.org/10.1139/t07-049.
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Thermal and frost action analyses in soils require the knowledge of the thermal conductivity of soil solid particles. This parameter was obtained using reverse modeling applied to thermal conductivity data of Quebec marine clays. Values ranged from 2.2 to 3.2 W/mK mostly due to variation of the quartz fraction. The mean thermal conductivity of forming minerals other than quartz was equal to 2.15 W/mK. A modified geometric mean model was thus proposed to estimate the thermal conductivity of clay solid particles based on the thermal conductivity of quartz and the mean thermal conductivity of the other minerals. Several data for soils in the literature were also analyzed to confirm the experimental results of this study and to further clarify the quartz fraction influence on the thermal conductivity of clay particles. Finally, analyses of basic geotechnical data from the literature helped establish empirical relationships for the estimation of the quartz fraction of a soil as a function of either the clay-size particle fraction or the liquid limit.
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Cui, Fu-Qing, Zhi-Yun Liu, Jian-Bing Chen, Yuan-Hong Dong, Long Jin, and Hui Peng. "Experimental Test and Prediction Model of Soil Thermal Conductivity in Permafrost Regions." Applied Sciences 10, no. 7 (2020): 2476. http://dx.doi.org/10.3390/app10072476.
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Soil thermal conductivity is a dominant parameter of an unsteady heat-transfer process, which further influences the stability and sustainability of engineering applications in permafrost regions. In this work, a laboratory test for massive specimens is performed to reveal the distribution characteristics and the parameter-influencing mechanisms of soil thermal conductivity along the Qinghai–Tibet Engineering Corridor (QTEC). Based on the measurement data of 638 unfrozen and 860 frozen soil specimens, binary fitting, radial basis function (RBF) neural network and ternary fitting (for frozen soils) prediction models of soil thermal conductivity have been developed and compared. The results demonstrate that, (1) particle size and intrinsic heat-conducting capacity of the soil skeleton have a significant influence on the soil thermal conductivity, and the typical specimens in the QTEC can be classified as three clusters according to their thermal conductivity probability distribution and water-holding capacity; (2) dry density as well as water content sometimes does not have a strong positive correlation with thermal conductivity of natural soil samples, especially for multiple soil types and complex compositions; (3) both the RBF neural network method and ternary fitting method have favorable prediction accuracy and a wide application range. The maximum determination coefficient (R2) and quantitative proportion of relative error within ±10% ( P ± 10 % ) of each prediction model reaches up to 0.82, 0.88, 81.4% and 74.5%, respectively. Furthermore, because the ternary fitting method can only be used for frozen soils, the RBF neural network method is considered the optimal approach among all three prediction methods. This study can contribute to the construction and maintenance of engineering applications in permafrost regions.
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Kokoreva, A. A., A. V. Kozhunov, M. A. Butylkina, I. V. Dymova, V. M. Stepanenko, and A. E. Ivanova. "Thermal conductivity of urban and artificial soils: methodological aspects and mathematical modeling." Dokuchaev Soil Bulletin, no. 118 (March 25, 2024): 128–66. http://dx.doi.org/10.19047/0136-1694-2024-118-128-166.
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There are various methods for experimental determination of the thermal conductivity dependence on soil moisture and substrates. The influence of the sample structure (monolith, bulk sample), sample temperature, the method of installing the probe into the sample on the obtained readings of the TEMPOS device was studied and methodological recommendations were proposed. The dependence of thermal conductivity of soils bulk samples and substrates on moisture is shown. The spread of thermal conductivity values in the moisture range from hygroscopic to full moisture capacity for soddy-podzolic soil is 0.229–1.430 W/(m*K), for peat – 0.250–0.521 W/(m*K), for sand – 0.280–2.605 W/(m*K), for a mixture – 0.234–1.568 W/(m*K). ). The influence of properties such as density, particle size distribution, specific surface area, organic matter content, salinity affected thermal properties to a lesser extent. The established patterns can be used to calculate the temperature regime of soils in solving a number of applied problems related to the construction of special soil objects, for example, when creating urban soil structures. For this, it is necessary either to determine the thermal conductivity experimentally, or to calculate it, using the physical parameters of soils and substrates. The first method is labor-consuming, the second is less accurate. As an example, the equations available for work in the HYDRUS-1D (Chang–Horton and Campbell) model are used. These equations either overestimate the thermal conductivity in the area of high substrate humidity, or underestimate the thermal conductivity in the area of low substrate humidity (sand, loam, peat and a mixture based on them).
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Musa, Mohamed S., Yu Lu, and John S. McCartney. "Improved Thermal Conductivity Function for Unsaturated Soil with Physics-based Parameters." E3S Web of Conferences 382 (2023): 06005. http://dx.doi.org/10.1051/e3sconf/202338206005.
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This paper proposes a new relationship between thermal conductivity and degree of saturation of unsaturated soils, referred to as the thermal conductivity function (TCF). The new sigmoidal relationship between thermal conductivity and degree of saturation was developed so that all parameters have a physical meaning. After calibration of the model using data from the literature and comparison with other available TCFs, the parameters of the new TCF were related to those of the soil-water retention curves for the soils investigated in the calibration process. The linkage between the parameters of the TCF and SWRC indicates that the parameters reflect the point of air entry and pore size distribution of the soil, as well as the maximum and minimum thermal conductivity values encountered at saturated and dry conditions, respectively.
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Massey, Jeffrey D., W. James Steenburgh, Sebastian W. Hoch, and Jason C. Knievel. "Sensitivity of Near-Surface Temperature Forecasts to Soil Properties over a Sparsely Vegetated Dryland Region." Journal of Applied Meteorology and Climatology 53, no. 8 (2014): 1976–95. http://dx.doi.org/10.1175/jamc-d-13-0362.1.
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AbstractWeather Research and Forecasting Model forecasts over the Great Salt Lake Desert erroneously underpredict nocturnal cooling over the sparsely vegetated silt loam soil area of Dugway Proving Ground in northern Utah, with a mean positive bias error in temperature at 2 m AGL of 3.4°C in the early morning [1200 UTC (0500 LST)]. Positive early-morning bias errors also exist in nearby sandy loam soil areas. These biases are related to the improper initialization of soil moisture and parameterization of soil thermal conductivity in silt loam and sandy loam soils. Forecasts of 2-m temperature can be improved by initializing with observed soil moisture and by replacing Johansen's 1975 parameterization of soil thermal conductivity in the Noah land surface model with that proposed by McCumber and Pielke in 1981 for silt loam and sandy loam soils. Case studies illustrate that this change can dramatically reduce nighttime warm biases in 2-m temperature over silt loam and sandy loam soils, with the greatest improvement during periods of low soil moisture. Predicted ground heat flux, soil thermal conductivity, near-surface radiative fluxes, and low-level thermal profiles also more closely match observations. Similar results are anticipated in other dryland regions with analogous soil types, sparse vegetation, and low soil moisture.
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Maina, Mohammed, Othniel Kamfani Likkason, Sani Ali, and Nuhu K. Samaila. "IMPACT OF CRUDE OIL POLLUTION ON SOIL THERMAL PROPERTIES (THERMAL CONDUCTIVITY, THERMAL DIFFUSIVITY AND THERMAL RESISTIVITY) IN OGONILAND RIVERS STATE SOUTH-SOUTH NIGERIA." FUDMA JOURNAL OF SCIENCES 9, no. 4 (2025): 324–34. https://doi.org/10.33003/fjs-2025-0904-3320.
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Soil thermal properties are required in many areas of engineering, agronomy, and soil science, and in recent years considerable effort has gone into developing techniques to determine these properties. Seed germination, seedling emergence, and subsequent stand establishment are influenced by the microclimate. Thermal properties of soils play an important role in influencing microclimate. In this study, the effect of soil thermal properties were assessed based on thermal conductivity, thermal diffusivity and thermal resistivity of soil samples polluted by crude oil and its spillage in Ogoniland Rivers State South-South Nigeria. Soil samples at different test points (locations) were collected at depths of 0 – 15 cm for topsoil and 15 – 30 cm for subsoil with the aid of Dutch stainless steel hand auger from four (4) sites (impacted) within the study area and one (non-impacted) control site (outside) the study area. Thermal properties (diffusivity, conductivity and resistivity) were determined and the soils at these specified depths and their values were compared to those outside the study areas (control sites). The results show that there are negligible effects of crude oil pollution on soil thermal properties in both impact site and non-impact site at different test points. The soils in Eleme, Gokana and Tai Local Government Areas were found to be fitted for agricultural activities, laying of gas pipeline and buried of cable for telecommunication industries. The thermal properties of the soil are within the values previously reported by previous researchers.
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Côté, Jean, and Jean-Marie Konrad. "A generalized thermal conductivity model for soils and construction materials." Canadian Geotechnical Journal 42, no. 2 (2005): 443–58. http://dx.doi.org/10.1139/t04-106.
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This paper intends to develop a generalized thermal conductivity model for moist soils that is based on the concept of normalized thermal conductivity with respect to dry and saturated states. This model integrates well the effects of porosity, degree of saturation, mineral content, grain-size distribution, and particle shape on the thermal conductivity of unfrozen and frozen soils. The thermal conductivity for saturated soils is computed with the use of a well-known geometric model that includes the unfrozen water content in frozen fine-grained soils. Nearly 220 experimental results available from the literature were analysed to develop a generalized empirical relationship to assess the thermal conductivity of dry soils. A general relationship between the normalized thermal conductivity of soils and the degree of saturation using a soil-type dependent factor was used to correlate the normalized thermal conductivity for more than 650 test results for unfrozen and frozen moist soils, such as gravels, sands, silts, clays, peat, and crushed rocks.Key words: heat transfer, soils, degree of saturation, mineral content, unfrozenfrozen, thermal conductivity.
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Calvet, Jean-Christophe, Noureddine Fritz, Christine Berne, Bruno Piguet, William Maurel, and Catherine Meurey. "Deriving pedotransfer functions for soil quartz fraction in southern France from reverse modeling." SOIL 2, no. 4 (2016): 615–29. http://dx.doi.org/10.5194/soil-2-615-2016.
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Abstract. The quartz fraction in soils is a key parameter of soil thermal conductivity models. Because it is difficult to measure the quartz fraction in soils, this information is usually unavailable. This source of uncertainty impacts the simulation of sensible heat flux, evapotranspiration and land surface temperature in numerical simulations of the Earth system. Improving the estimation of soil quartz fraction is needed for practical applications in meteorology, hydrology and climate modeling. This paper investigates the use of long time series of routine ground observations made in weather stations to retrieve the soil quartz fraction. Profile soil temperature and water content were monitored at 21 weather stations in southern France. Soil thermal diffusivity was derived from the temperature profiles. Using observations of bulk density, soil texture, and fractions of gravel and soil organic matter, soil heat capacity and thermal conductivity were estimated. The quartz fraction was inversely estimated using an empirical geometric mean thermal conductivity model. Several pedotransfer functions for estimating quartz content from gravimetric or volumetric fractions of soil particles (e.g., sand) were analyzed. The soil volumetric fraction of quartz (fq) was systematically better correlated with soil characteristics than the gravimetric fraction of quartz. More than 60 % of the variance of fq could be explained using indicators based on the sand fraction. It was shown that soil organic matter and/or gravels may have a marked impact on thermal conductivity values depending on which predictor of fq is used. For the grassland soils examined in this study, the ratio of sand-to-soil organic matter fractions was the best predictor of fq, followed by the gravimetric fraction of sand. An error propagation analysis and a comparison with independent data from other tested models showed that the gravimetric fraction of sand is the best predictor of fq when a larger variety of soil types is considered.
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Zakharov, A. V., and S. E. Makhover. "THE EFFECT GRAIN-SIZE COMPOSITION ON THERMAL CONDUCTIVITY OF SANDY SOILS." Construction and Geotechnics 11, no. 2 (2020): 19–27. http://dx.doi.org/10.15593/2224-9826/2020.2.02.
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Today the issue of energy saving is acute. The main sources of energy are radiant energy of the Sun, wind energy, energy of moving water. Therefore, the issue of solving alternative energy sources is relevant. The article aims to solve the problem by using low-potential heat of the soil mass by means of energy-efficient building constructions - foundations. It is necessary to know the thermal characteristics of soils for this. At the moment, methods for determining the thermophysical properties of inert materials with subsequent practical application in the field of construction have been widely studied, but no one of these methods takes into account the grain-size composition. Thus, the study of the connection between the thermal conductivity and the grain-size composition of the soil is important. The aim of the work is to Estimation of thermal conductivity of sandy soils based on grain-size composition. This article presents an analysis of the dependence of the thermal conductivity of the sandy soil of its grain-size composition. The matrix of experiment planning is made; the methodology and technological sequence of the experiment were tested. Statistical processing of the obtained experimental data was carried out. Based on a series of test experiments, it was concluded that there are two factors competing in its thermal conductivity: an increase in λ due to an increase in the degree of pore filling and a decrease in total heat conductivity due to a decrease in the degree of pore filling. These results suggest that grain-size composition has an impact on the thermal conductivity of the sandy soil. During the experiment, the dependence of the thermal conductivity of sandy soils on their grain-size composition was experimentally established.
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Yi, S., J. Chen, Q. Wu, and Y. Ding. "Simulating the role of gravel on the dynamics of permafrost on the Qinghai-Tibetan Plateau." Cryosphere Discussions 7, no. 5 (2013): 4703–40. http://dx.doi.org/10.5194/tcd-7-4703-2013.
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Abstract. Gravel (particle size ≥ 2 mm) is common in soil profiles of the Qinghai-Tibetan Plateau (QTP). It has different thermal and hydrological properties than other fine mineral soils (particle size < 2 mm), which may have significant impacts on the thermal and hydrological processes of soil. However, few models have considered gravel. In this study, we implemented the thermal and hydraulic properties of gravel into the Dynamic Organic Soil-Terrestrial Ecosystem Model to develop new schemes to simulate the dynamics of permafrost on the QTP. Results showed that: (1) the widely used Farouki thermal scheme always simulated higher thermal conductivity of frozen soils than unfrozen soils with the same soil water content; therefore it tends to overestimate permafrost thickness strongly; (2) there exists a soil moisture threshold, below which the new set of schemes with gravel simulated smaller thermal conductivity of frozen soils than unfrozen soils; (3) soil with gravel has higher hydraulic conductivity and poorer water retention capability; and simulations with gravel were usually drier than those without gravel; and (4) the new schemes simulated faster upward degradation than downward degradation; and the simulated permafrost thicknesses were sensitive to the fraction of gravel, the gravel size, the thickness of soil with gravel, and the subsurface drainage. To reduce the uncertainties in the projection of permafrost degradation on the QTP, more effort should be made to: (1) developing robust relationships between soil thermal and hydraulic properties and gravel characteristics based on laboratory work; and (2) compiling spatial datasets of the vertical distribution of gravel content based on measurements during drilling or the digging of soil pits.
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Baker, T. H. W., and L. E. Goodrich. "Measurement of soil water content using the combined time-domain reflectometry – thermal conductivity probe." Canadian Geotechnical Journal 24, no. 1 (1987): 160–63. http://dx.doi.org/10.1139/t87-016.
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A two-pronged metal probe measures the thermal conductivity and apparent dielectric constant of soils in the laboratory and in the field. One prong acts as a transient line heat source probe in measuring thermal conductivity. The apparent dielectric constant of the soil is determined by the time-domain reflectometry (TDR) technique, using both prongs as a parallel transmission line. Volumetric water content is determined from the apparent dielectric constant, making use of an empirical relation valid for most soils. For volumetric water contents above about 8%, the apparent dielectric constant shows a strong dependence on water content and relatively small changes can be measured; sensitivity increases with water content. For volumetric water contents less than 8%, a soil-dependent empirical relation between water content and thermal conductivity has been developed that is most sensitive at lower water contents. The combined probe provides a means of monitoring the water content of soils over a wide range of values, in the field and in the laboratory. Key words: soil water content, time-domain reflectometry, thermal conductivity.
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Wang, Yi, and Guo Min Shen. "The Primary and Secondary Analysis of Uncertain Factors in Soil Thermal Properties for GSHP." Advanced Materials Research 614-615 (December 2012): 688–94. http://dx.doi.org/10.4028/www.scientific.net/amr.614-615.688.
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In this paper, at first, an effective soil thermal conductivity model was established. Single factor regression analysis for 6 uncertain factors contained in the model was then conducted respectively. Finally, the primary and secondary characters of these uncertain factors were analyzed by using the orthogonal test. The analysis results show that the effective soil thermal conductivity has linear relationships with the saturation degree of unsaturated soil and the depth of water table and has power function relationships with other 4 uncertain factors; the porosity of unsaturated soil has the greatest effect on the effective soil thermal properties, followed by saturation degree of unsaturated soil, porosity of saturated soil, solid phase thermal conductivity of unsaturated soil, solid phase thermal conductivity of saturated soil and the depth of water table.
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Yurttakal, Ahmet. "Extreme gradient boosting regression model for soil thermal conductivity." Thermal Science 25, Spec. issue 1 (2021): 1–7. http://dx.doi.org/10.2298/tsci200612001y.
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The thermal conductivity estimation for the soil is an important step for many geothermal applications. But it is a difficult and complicated process since it involves a variety of factors that have significant effects on the thermal conductivity of soils such as soil moisture and granular structure. In this study, regression was performed with the extreme gradient boosting algorithm to develop a model for estimating thermal conductivity value. The performance of the model was measured on the unseen test data. As a result, the proposed algorithm reached 0.18 RMSE, 0.99 R2, and 3.18% MAE values which state that the algorithm is encouraging.
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Kaneza, Nice, Aashish Pokhrel, Laureano R. Hoyos, and Xinbao Yu. "Thermally Induced Moisture Flow in a Silty Sand under a 1-D Thermal Gradient." Geosciences 14, no. 8 (2024): 207. http://dx.doi.org/10.3390/geosciences14080207.
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Thermally induced moisture flow in unsaturated soils involves complex coupled thermal–hydro processes with the moisture flow in both the vapor and liquid phases. The accurate measurement of the moisture flow in unsaturated sands remains a challenging task due to low moisture migration, the temperature effect on moisture sensors, and the gravity effect on moisture flow. This study aims to accurately measure transient moisture flow, heat transfer, and thermal conductivity in a silty sand with 35% non-plastic fines in a closed heat cell with a controlled 1-D temperature gradient. The heat cell consists of two temperature-controlled heat exchanger plates, heat flux sensors, moisture sensors, thermocouples, and thermal conductivity sensors. The soil moisture sensors were calibrated in the test soil at room temperature and then at elevated incremental temperatures. Soil samples compacted at various initial moisture contents were tested under a constant 1-D temperature gradient of 4 °C/cm. Soil moisture redistribution, temperature, and thermal conductivity profiles were determined from the test results. Transient temperature responses indicated that a lower initial moisture content led to a higher temperature drop after reaching the peak, or a more concaved temperature profile in a steady state due to enhanced moisture migration driven by the temperature gradients. Dry soils exhibited uniform thermal properties, while moist soils showed varying thermal conductivity profiles. A critical moisture content was identified when the maximum moisture migration occurred. Thermal conductivity in soils increased with the distance from the heat source due to thermally induced moisture migration. These findings provide valuable insights into coupled moisture–heat flow dynamics in unsaturated sands.
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Calvet, J. C., N. Fritz, C. Berne, B. Piguet, W. Maurel, and C. Meurey. "Impact of gravels and organic matter on the thermal properties of grassland soils in southern France." SOIL Discussions 2, no. 1 (2015): 737–65. http://dx.doi.org/10.5194/soild-2-737-2015.
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Abstract. Soil moisture is the main driver of temporal changes in values of the soil thermal conductivity. The latter is a key variable in land surface models (LSMs) used in hydrometeorology, for the simulation of the vertical profile of soil temperature in relation to soil moisture. Shortcomings in soil thermal conductivity models tend to limit the impact of improving the simulation of soil moisture in LSMs. Models of the thermal conductivity of soils are affected by uncertainties, especially in the representation of the impact of soil properties such as the volumetric fraction of quartz (q), soil organic matter, and gravels. As soil organic matter and gravels are often neglected in LSMs, the soil thermal conductivity models used in most LSMs represent the mineral fine earth, only. Moreover, there is no map of q and it is often assumed that this quantity is equal to the volumetric fraction of sand. In this study, q values are derived by reverse modelling from the continuous soil moisture and soil temperature sub-hourly observations of the Soil Moisture Observing System – Meteorological Automatic Network Integrated Application (SMOSMANIA) network at 21 grassland sites in southern France, from 2008 to 2015. The soil temperature observations are used to retrieve the soil thermal diffusivity (Dh) at a depth of 0.10 m in unfrozen conditions, solving the thermal diffusion equation. The soil moisture and Dh values are then used together with the measured soil properties to retrieve soil thermal conductivity (λ) values. For ten sites, the obtained λ value at saturation (λsat) cannot be retrieved or is lower than the value corresponding to a null value of q, probably in relation to a high density of grass roots at these sites or to the presence of stones. For the remaining eleven sites, q is negatively correlated with the volumetric fraction of solids other than sand. The impact of neglecting gravels and organic matter on λsat is assessed. It is shown that these factors have a major impact on λsat.
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Morais, Thaise da Silva Oliveira, Cristina de Hollanda Cavalcanti Tsuha, and Orencio Monje Vilar. "Thermal properties of a tropical unsaturated soil." MATEC Web of Conferences 337 (2021): 01019. http://dx.doi.org/10.1051/matecconf/202133701019.
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Ground thermal properties, especially the thermal conductivity, are of paramount importance for the design of ground source heat pump systems (GSHP), used for space heating and cooling. However, very little information, if any, are available from the thermal characteristics of tropical unsaturated soils related to the GSHP application. To evaluate the thermal behaviour of a typical Brazilian tropical unsaturated soil, an extensive experimental investigation was conducted at the test site of the University of Sao Paulo at São EESC/USP) comprising Carlos (a detailed soil characterization; field monitoring of the seasonal groundwater table variation; soil and ambient temperatures, and matric suction of the top soil. This paper describes the investigation program and compares the thermal soil properties as measured in laboratory and field thermal response tests. The results were variable depending on the testing techniques; however, all results showed that the soil thermal conductivity is strongly influenced by the degree of saturation of the soil.
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Ji, Yadong, Kaipeng Zhu, Chao Lyu, et al. "Semiempirical Correlation between P-Wave Velocity and Thermal Conductivity of Frozen Silty Clay Soil." Shock and Vibration 2021 (April 12, 2021): 1–7. http://dx.doi.org/10.1155/2021/5533696.
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In this study, the thermal conductivity and P-wave velocity of silty clay soil with different water contents are investigated through experiments at different temperatures, and a theoretical correlation between thermal conductivity and wave velocity is established. With temperature decline, the unfrozen water content is reduced and frost heave cracks propagate in soil samples. The variations in thermal conductivity and P-wave velocity are summarized as four phases. The freezing temperature of silty clay soil is between −2°C and −4°C. There is an inversely proportional relationship between thermal conductivity and P-wave velocity for silty clay soil at temperatures below freezing. The experimental results show that the theoretical correlation can well explain the relationship between P-wave velocity and thermal conductivity. These findings provide a possibility for determining the thermal conductivity easily and quickly in geothermal systems and underground engineering projects.
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Goodrich, L. E. "Field measurements of soil thermal conductivity." Canadian Geotechnical Journal 23, no. 1 (1986): 51–59. http://dx.doi.org/10.1139/t86-006.
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Data representing the seasonal variation of thermal conductivity of the ground at depths within the seasonally active freezing/thawing zone are presented for a number of different soil conditions at four sites across Canada. An inexpensive probe apparatus suitable for routine field measurements is described.In all the cases examined, significant seasonal variations were confined to the first few decimetres. In addition to distinct seasonal differences associated with phase change, quite large changes occurred during the period when the soil was thawed in those cases where seasonal drying was possible. Below the seasonally active zone, thawed soil conductivities did not differ greatly among the three nonpermafrost sites in spite of soil composition ranging from marine clay to sandy silt. The data suggest that, even within a given soil layer, quite significant differences in thermal conductivity may be encountered in engineering structures such as embankments, presumably because of differences in drainage conditions. Key words: thermal conductivity, field measurements, phase relationships, drying, permafrost, clay, silt, peat.
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Alrtimi, A., M. Rouainia, and S. Haigh. "Thermal conductivity of a sandy soil." Applied Thermal Engineering 106 (August 2016): 551–60. http://dx.doi.org/10.1016/j.applthermaleng.2016.06.012.
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He, Hailong, Min Li, Miles Dyck, Bingcheng Si, Jinxin Wang, and Jialong Lv. "Modelling of soil solid thermal conductivity." International Communications in Heat and Mass Transfer 116 (July 2020): 104602. http://dx.doi.org/10.1016/j.icheatmasstransfer.2020.104602.
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Sorour, M. M., M. M. Saleh, and R. A. Mahmoud. "Thermal conductivity and diffusivity of soil." International Communications in Heat and Mass Transfer 17, no. 2 (1990): 189–99. http://dx.doi.org/10.1016/0735-1933(90)90053-m.
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Sattler, Pamela, and D. G. Fredlund. "Use of thermal conductivity sensors to measure matric suction in the laboratory." Canadian Geotechnical Journal 26, no. 3 (1989): 491–98. http://dx.doi.org/10.1139/t89-063.
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The measurement of soil suction is pivotal to the application of soil mechanics principles in geotechnical engineering practice related to unsaturated soils. Volume change, shear strength, and seepage analyses all require an understanding of the matric suction in the soil. This note summarizes the use of thermal conductivity sensors to measure matric suction in the laboratory. The thermal conductivity sensor is described along with its mode of operation. A brief description is given of the procedure for calibrating thermal conductivity sensors using a pressure plate apparatus. The measurement of matric suction can be performed in the laboratory on Shelby tube samples. The laboratory measurements of matric suction can be adjusted for the effect of overburden pressure in the field. The required equilibration time for suction measurements is discussed along with details of the test procedure. The applications of the measured suction values to design are briefly discussed.Key words: matric suction, negative pore-water pressure, thermal conductivity sensor, laboratory, undisturbed samples.
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Liu, Chenyang, Xinmin Hu, Ren Yao, et al. "Assessment of Soil Thermal Conductivity Based on BPNN Optimized by Genetic Algorithm." Advances in Civil Engineering 2020 (December 22, 2020): 1–10. http://dx.doi.org/10.1155/2020/6631666.
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Thermal conductivity is a critical parameter playing an important role in the heat transfer process in thermal engineering and enormous other engineering fields. Thus, the accurate acquisition of thermal conductivity has significant meaning for thermal engineering. However, compared to density test, moisture content test, and other physical property tests, the thermal conductivity is hard and expensive to acquire. Apparently, it has great meaning to accurately predict conductivity around a site through easily accessible parameters. In this paper, 40 samples are taken from 37 experimental points in Changchun, China, and the BPNN optimized by genetic algorithm (GA-BPNN) is used to evaluate the thermal conductivity by moisture content, porosity, and natural density of undisturbed soil. The result is compared by two widely used empirical methods and BPNN method and shows that the GA-BPNN has better prediction ability for soil thermal conductivity. The impact weight is obtained through mean impact value (MIV), where the natural density, moisture content, and porosity are 30.98%, 55.57%, and 13.45%, respectively. Due to high complexity of different parameter on thermal conductivity, some remolded soil specimens are taken to study the influence of individual factors on thermal conductivity. The correlations between moisture content and porosity with thermal conductivity are studied through control variable method. The result demonstrates that the impact weight of moisture content and porosity can be explained by remolded soil experiment to some extent.
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Cheng, Liang, Natalia Afur, and Mohamed A. Shahin. "Bio-Cementation for Improving Soil Thermal Conductivity." Sustainability 13, no. 18 (2021): 10238. http://dx.doi.org/10.3390/su131810238.
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A promising technology for renewable energy is energy piles used to heat and cool buildings. In this research, the effects of bio-cementation via microbially induced calcite precipitation (MICP) using mixed calcium and magnesium sources and the addition of fibres on the thermal conductivity of soil were investigated. Firstly, silica sand specimens were treated with cementation solutions containing different ratios of calcium chloride and magnesium chloride to achieve maximum thermal conductivity improvement. Three treatment cycles were provided, and the corresponding thermal conductivity was measured after each cycle. It was found that using 100% calcium chloride resulted in the highest thermal conductivity. This cementation solution was then used to treat bio-cemented soil samples containing fibres, including polyethylene, steel and glass fibres. The fibre contents used included 0.5%, 1.0% and 1.5% of the dry sand mass. The results show that the glass fibre samples yielded the highest thermal conductivity after three treatment cycles, and SEM imaging was used to support the findings. This research suggests that using MICP as a soil improvement technique can also improve the thermal conductivity of soil surrounding energy piles, which has high potential to effectively improve the efficiency of energy piles.
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Tai, Pei, Chao Zhou, Yubo Zhou, and Sheqiang Cui. "Thermal conductivity of Toyoura sand at various moisture and stress conditions." E3S Web of Conferences 205 (2020): 04010. http://dx.doi.org/10.1051/e3sconf/202020504010.
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Thermal conductivity of soils is a crucial characteristic in various geotechnical applications, such as geothermal pumps, energy piles and buried pipelines. Previous researchers have done extensive works on the factors that may affect the soil thermal conductivity, including soil porosity, degree of saturation, mineralogy, testing temperatures, particle size and gradation. A modified oedometer frame that can incorporate the transient heat probe method is adopted to investigate the influence of stress state on thermal conductivity of Toyoura sand. Preliminary test under 1-D compression shows that the thermal conductivity of sand increases with the rise of vertical stress, and the variation exhibits hysteresis during a loading and unloading cycle. In addition, the effects of void ratio and water content were also studied and test results agreed well with previous values reported in the literature.
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Bristow, KL, RD White, and GJ Kluitenberg. "Comparison of single and dual probes for measuring soil thermal properties with transient heating." Soil Research 32, no. 3 (1994): 447. http://dx.doi.org/10.1071/sr9940447.
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Storage and transfer of heat in soils is governed by the soil thermal properties and these properties are therefore needed in many agricultural and engineering applications. In this paper we discuss solutions of the heat flow equation applicable to single and dual probe transient heating methods, and describe measurements made on air-dry sand to show how these methods can be used to obtain soil thermal properties. Measurements show that the two methods yield similar values of thermal conductivity. When determining thermal conductivity from the single probe data, it is best to use nonlinear curve fitting and to include a correction term in the model to account for the presence of the probe. Measurements of volumetric heat capacity made by using the dual probe heat-pulse method agreed well with independent estimates obtained using the de Vries method of summing the heat capacities of the soil constituents. The advantage of using the dual probe method together with the appropriate heat-pulse theory rather than the single probe is that all three soil thermal properties, the thermal diffusivity, volumetric heat capacity, and thermal conductivity, can be determined from a single heat-pulse measurement. Instantaneous heat-pulse theory can be used with the dual probe method to determine heat capacity from short duration heat-pulse data, but it should not be used to determine the thermal diffusivity and thermal conductivity.
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Gorban, V. A. "Features of soil thermophysical properties of the southern variant of ravine biogeocenoses of the Ukrainian steppe zone." Ecology and Noospherology 31, no. 2 (2020): 82–86. http://dx.doi.org/10.15421/032013.
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Thermophysical properties are an important characteristic of the general condition of soils, which determine the peculiarities of the distribution of heat flow in them. Today studies of thermophysical properties of soils, including the steppe zone of Ukraine, are practically not performed. This determines the relevance of the work, which is devoted to establishing the characteristics of the thermal properties of various soils. As a result of the study of thermal diffusivity, heat capacity and thermal conductivity of soils of northern and southern exposures, as well as the thalweg of the Voyskovoy Bayrak (located near the village of Voyskovoe Solonyansky district of Dnipropetrovsk region), it was found that the most important soil factors particles of physical clay and organic matter content. It was found that the eluvial horizons of the chernozem of the forest of the northern exposure differ in the reduced values of heat capacity and thermal conductivity in comparison with the illuvial horizons. Eluvial horizons of forest-meadow soil of thalweg are characterized by increased values of thermal diffusivity and thermal conductivity, as well as reduced values of heat capacity compared to illuvial horizons. Eluvial horizons of forest chernozem of southern exposure are characterized by lower values of thermal diffusivity, heat capacity and thermal conductivity compared to illuvial horizons. The most significant boundary between eluvial and illuvial horizons in terms of thermophysical properties is characteristic of the chernozem of forest southern exposure, which is manifested in a sharp increase in the values of thermophysical properties in the first illuvial horizon. Cluster analysis revealed that the most similar in terms of thermal diffusivity are forest chernozems of southern and northern exposures, and in terms of heat capacity and thermal conductivity – forest chernozems of northern exposure and forest-meadow soil of thalweg ravine.
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Garg, Ankit, Sai Krishna Akash Ramineni, Xuekun Liu, Mingjie Jiang, and Neelima Satyam. "Theoretical and Experimental Investigation of Thermal Conductivity of Unsaturated Soils Amended with a Sustainable Biochar." Sustainability 16, no. 23 (2024): 10564. https://doi.org/10.3390/su162310564.
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This study investigates the thermal conductivity of unsaturated kaolin soil amended with biochar to promote sustainable geotechnical engineering. Biochar from agricultural waste offers the dual benefits of carbon sequestration and sustainable waste management. Experimental measurements were conducted for kaolin soil with 0% (control) and 10% biochar under varying moisture contents. Peach pit biochar increased thermal conductivity by 2–3% at 30–40% saturation and 40–50% at higher saturation as compared to the bare soil. Reed biochar decreased thermal conductivity by 1–2% at lower saturation but increased it by 55–60% at higher saturation. Applewood biochar increased thermal conductivity by 35–50% at moderate saturation, decreased beyond 50% water content, and had minimal variation at lower saturation. Further, the existing empirical models (such as Kersten and the Johansen model, Wiener’s model, and Mickley’s model) for predicting the thermal conductivity of materials were validated using the measured results of biochar-amended soils. Adding 10% biochar reduces thermal conductivity by 34.8%, and the Haigh model (2012) fits best with high accuracy and lower RMSE values than models such as Kersten and Johansen, which appears to be less reliable in case of biochar-amended soils. With an addition of biochar, the R2 values of the models decreased from a range of 0.8 to 0.9 to a range of 0.4–0.6, indicating the need for better model adaptation. Wiener bounds accurately predicted thermal conductivity at low saturation levels but varied greatly at higher ones. The most variable sample was peach pit biochar, highlighting the need to refine predictive models for material-specific differences. These findings provide a foundation for developing improved predictive models and integrating biochar into sustainable geotechnical and geothermal systems.
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Soltanpour, Sara, and Adolfo Foriero. "Numerical Modelling of Coupled Thermal–Hydraulic–Mechanical Processes in Unsaturated Soils During Freezing and Thawing." Water 17, no. 5 (2025): 677. https://doi.org/10.3390/w17050677.
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Most existing studies investigate the effect of the overburden pressure and external temperature on the freezing process in unsaturated soils. However, the hydraulic and thermal properties of soil have a significant outcome as well. For this purpose, a coupled Thermal–Hydraulic–Mechanical theory, to investigate unsaturated fine sands, is developed and deployed in a finite element method simulation with COMSOL Multiphysics. Validation of the model’s accuracy is achieved by comparing the numerical to the experimental soil freezing and thawing results published in the literature. After validating the model’s reliability, five cases are simulated to examine the impact of soil particle thermal conductivity and saturated hydraulic conductivity on the freezing and thawing processes. Results indicate that the saturated hydraulic conductivity has a slightly greater effect on the position of the freezing front and on the amount of heave than particle thermal conductivity. Finally, this study shows the effect inflicted by the temperature gradient, water flux, and vertical stress build-up on both thermal and hydraulic properties during the freeze–thaw cycles.
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Wu, Bing, Hong-Hu Zhu, and Dingfeng Cao. "Measuring thermal conductivity of frozen soil using fiber optic sensors." BULLETIN of L.N. Gumilyov Eurasian National University. Technical Science and Technology Series 135, no. 2 (2021): 82–93. http://dx.doi.org/10.32523/2616-7263-2021-135-2-82-93.
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The thermal conductivity is crucial for determining heat transfer in frozen soil. However, it is a challenge to obtain accurate measurement values due to the instability of soil properties. Recently, the fiber optic sensing technologies has enabled accurate and distributed in-situ monitoring of a variety of geotechnical parameters. This paper aims to explore the feasibility of actively heated fiber Bragg grating (AH-FBG) method in measuring thermal conductivity of frozen soil. A series of laboratory experiments were performed on frozen soil samples at different initial temperatures from −16 to 5 ℃. The theoretical upper and lower limits of thermal conductivity were used to evaluate the AHFBG measurements. The thermal conductivity recorded by a heat transfer analyzer was used to identify the measurement accuracy. The experimental results that the AH-FBG method can accurately measure the thermal conductivity of frozen soil when the initial temperature is below −6 ℃, and the measurement error is within acceptable range of 0.8%. When the soil temperature is between −6 and 0 ℃, significant measurement errors were observed due to the disturbance of heating to the frozen soil.
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Gorban, V. A. "Soil thermal properties of forest biogeocenoses in steppe zone as a diagnostic indicator of their soil genesis." Fundamental and Applied Soil Science 19, no. 1 (2019): 26–30. http://dx.doi.org/10.15421/041905.
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Soil is a specific natural body, which is characterized by a number of features due to which it differs from living organisms and rocks. One of these features is its thermal properties. The most important thermal properties of the soil are thermal conductivity, thermal capacity and thermal diffusivity, which reflect the specific features of the set of properties inherent in different soils. As a result of the studies, the existence of a direct relationship between the values of thermal conductivity and thermal diffusivity of Calcic Chernozem and the content of the silt fraction in them, as well as between the thermal capacity and the content of organic matter in them. The established relations do not appear clearly in Luvic Chernozem and Chernic Phaeozem. The maximum thermal properties for Luvic Chernozem and Chernic Phaeozem were found in the eluvial horizon, which in the lower part borders on the illuvial horizon. The eluvial horizons of Luvic Chernozem and Chernic Phaeozem are characterized by lower thermal properties compared with the illuvial horizons. The thermal properties of soils can be used to clarify the distribution characteristics of the silt fraction and organic matter along the profile, as well as determination of the intensity of eluvial-illuvial processes. The establishment of these soil features is an important characteristic of their soil genesis, which is especially important for chernozem soils under forest vegetation.
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Drzyzga, Agnieszka. "Review of series-parallel models for calculating the thermal conductivity of soils." E3S Web of Conferences 323 (2021): 00008. http://dx.doi.org/10.1051/e3sconf/202132300008.
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The paper presents mixed models collected from the literature for calculating the thermal conductivity of the soil. They are created on the basis of combining the serial and parallel model. The thermal conductivity of the soil is the basic thermal parameter of the soil. Knowledge of it is necessary, among other things, for the proper design of underground infrastructure. The combination of models will help you to choose the method of calculating the thermal conductivity of the soil that gives the most accurate results and has the lowest error.
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Levy, Joseph S., and Logan M. Schmidt. "Thermal properties of Antarctic soils: wetting controls subsurface thermal state." Antarctic Science 28, no. 5 (2016): 361–70. http://dx.doi.org/10.1017/s0954102016000201.
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AbstractMineral soils in the McMurdo Dry Valleys (MDV), Antarctica, are commonly considered to be dry, and therefore to be good insulators with low thermal diffusivity values (~0.2 mm2s-1). However, field measurements of soil moisture profiles with depth, coupled with observations of rapid ground ice melt, suggest that the thermal characteristics of MDV soils, and thus their resistance to thaw, may be spatially variable and strongly controlled by soil moisture content. The thermal conductivity, heat capacity and thermal diffusivity of 17 MDV soils were measured over a range of soil moisture conditions from dry to saturated. We found that thermal diffusivity varied by a factor of eight for these soils, despite the fact that they consist of members of only two soil groups. The thermal diffusivity of the soils increased in all cases with increasing soil moisture content, suggesting that permafrost and ground ice thaw in mineral soils may generate a positive thawing feedback in which wet soils conduct additional heat to depth, enhancing rates of permafrost thaw and thermokarst formation.
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Jong van Lier, Quirijn de, and Angelica Durigon. "Soil thermal diffusivity estimated from data of soil temperature and single soil component properties." Revista Brasileira de Ciência do Solo 37, no. 1 (2013): 106–12. http://dx.doi.org/10.1590/s0100-06832013000100011.
Full textAbstract:
Under field conditions, thermal diffusivity can be estimated from soil temperature data but also from the properties of soil components together with their spatial organization. We aimed to determine soil thermal diffusivity from half-hourly temperature measurements in a Rhodic Kanhapludalf, using three calculation procedures (the amplitude ratio, phase lag and Seemann procedures), as well as from soil component properties, for a comparison of procedures and methods. To determine thermal conductivity for short wave periods (one day), the phase lag method was more reliable than the amplitude ratio or the Seemann method, especially in deeper layers, where temperature variations are small. The phase lag method resulted in coherent values of thermal diffusivity. The method using properties of single soil components with the values of thermal conductivity for sandstone and kaolinite resulted in thermal diffusivity values of the same order. In the observed water content range (0.26-0.34 m³ m-3), the average thermal diffusivity was 0.034 m² d-1 in the top layer (0.05-0.15 m) and 0.027 m² d-1 in the subsurface layer (0.15-0.30 m).