Temperature effects become important in a number of geotechnical applications, such as nuclear waste disposal facilities, buried high-voltage cables, pavement, energy geostructures and geothermal energy. On the other hand, soft soils act time- and strain rate dependent. Both temperature and strain rate influence soil behavior, affecting stiffness, strength, and deformation even under constant stress levels. A model to predict temperature and loading rate effects on soil behavior is presented in this article. The model is based on a simple visco-hypooplastic model for clays and encompasses key aspects of coupled rate- and temperature-dependent soil behavior such as (partially irreversible) thermal expansion, heating-induced irreversible compression, stress history, drained heating/cooling cycles, as well as mechanical and thermal creep, incorporating isotachs, and isotherms.

Uranyl ions (UO22+) are the form of uranium usually dissolved in water and are radioactive and can cause serious damage to the environment. Adsorption of uranyl ions is a critical method for removing and safely storing radioactive materials that harm the environment. It is also an important tool for combating water and soil contamination, managing nuclear waste and environmental sustainability. Polymer-based composites were developed for this purpose. Polymer-based composites enable the efficient removal of harmful and radioactive uranium compounds from water and soil. Through the incorporation of polymers and fillers (such as zeolite), materials with specific properties capable of adsorbing uranyl ions with high efficiency can be designed. The ratio of the components constituting the composites can be adjusted to optimize the adsorption capacity, as well as the chemical and thermal behaviors. Two composites were created: P(MA-Z50), consisting of ethylene glycol dimethacrylate (EGDM), methacrylic acid (MA), and zeolite, and P(MA-Z75), which contained a higher amount of zeolite. These composites were synthesized at room temperature and analyzed using various techniques such as Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). The study investigated the effects of adsorbent quantity, adsorbate concentration, temperature, time, and pH on adsorption efficiency and capacity. The Langmuir adsorption isotherm provided the best fit for uranium (VI) adsorption. The results showed that rapid adsorption occurred within the first 100 min, with the rate slowing down until equilibrium was reached after 360 min. The pseudo-second-order kinetic model best described the adsorption process.

This paper presents a general method for defining the macroscopic free-energy density function and its complementary forms for a porous medium saturated by two non-miscible fluids, in the case of compressible fluid and solid constituents, non-isothermal conditions and negligible interfacial surface energy. The major advantage of the proposed approach is that no limitation or simplification is posed on the choice of the free energies of the fluid constituents. As a result, a fully non-linear equation of state for the pore fluids can be incorporated within the proposed framework. The method is presented under the assumption that interfacial surface energy terms are negligible, thus recovering a Bishop parameter chi coinciding with the degree of saturation, which is expected to be applicable mostly to non-plastic soils. Moreover, small strains of the solid skeleton are assumed, but the method can be easily extended to a large strain formulation as discussed below. The paper analyzes also some particular cases concerning the incompressibility of all constituents, the geometric linearization and the incompressibility only of the solid constituent. The knowledge of the free energy density function is the starting point for the evaluation of the dissipation function, of energy and entropy balance and, in general, for the formulation of thermodynamically consistent constitutive models.

This study investigates the influence of primary variables selection on modeling non-isothermal two-phase flow, using numerical simulation based on the full-scale engineered barrier system (EBS) experiment conducted at the Horonobe Underground Research Laboratory (URL) as part of the DECOVALEX-2023 project. A thermalhydraulic coupled model was validated against analytical solution and experimental data before being applied to simulate the heterogeneous porous media within the EBS. Two different primary variable schemes were compared for discretizing the governing equations, revealing substantial differences in results. Notably, using capillary pressure as a primary variable instead of saturation resulted in closer alignment with analytical solutions and real-world observations. While the modeling work at the Horonobe URL generally exhibited trends consistent with experimental data, discrepancies were attributed to the operational conditions of the heater and the influence of the Excavation Damaged Zone (EDZ) near the borehole.

In this article, a one-dimensional non-isothermal diffusion model for organic pollutant in an unsaturated composite liner (comprising a geomembrane and an unsaturated compacted clay liner (CCL)) considering the degradation effect is established, which also includes the impacts of temperature on diffusion-related parameters, and employs a water content and pore-water pressure head relationship equation that better matches the experimental results. Subsequently, this model is addressed through a finite-difference technique, and its reasonableness is proved by comparing with the experiment measurements and two other calculation approaches. Following this, the analyses suggest that the diffusion coefficients' change induced by a rising temperature accelerates the diffusion rate, whereas such an alteration on partitioning coefficients has an opposite effect. Furthermore, the evaluation reveals that the non-isothermal state caused by an increasing upper temperature overall lowers the anti-fouling performance. The unsaturated composite liner's barrier function is weakened by an increment in residual water content of CCL, but enhanced by unsaturated layer thickness. It is also detected that the degradation effect should be considered if the degradation half-life <= 100 years. Lastly, a simplified approach for assessing the unsaturated composite liner's barrier performance is presented, which can provide guidance for its engineering design in a non-isothermal scenario.

Increased anthropogenic activities over the last decades have led to a gradual increase in chromium (Cr) content in the soil, which, due to its high mobility in soil, makes Cr accumulation in plants a serious threat to the health of animals and humans. The present study investigated the ameliorative effect of foliar-applied Si nanoparticles (SiF) and soil-applied SiNPs enriched biochar (SiBc) on the growth of wheat in Cr-polluted soil (CPS). Two levels of CPS were prepared, including 12.5 % and 25 % by adding Cr-polluted wastewater in the soil as soil 1 (S1) and soil 2 (S2), respectively for the pot experiment with a duration of 40 days. Cr stress significantly reduced wheat growth, however, combined application of SiF and SiBc improved root and shoot biomass production under Cr stress by (i) reducing Cr accumulation, (ii) increasing activities of antioxidant enzymes (ascorbate peroxidase and catalase), and (iii) increasing protein and total phenolic contents in both root and shoot respectively. Nonetheless, separate applications of SiF and SiBc effectively reduced Cr toxicity in shoot and root respectively, indicating a tissue-specific regulation of wheat growth under Cr. Later, the Langmuir and Freundlich adsorption isotherm analysis showed a maximum soil Cr adsorption capacity similar to Q((max)) of 40.6 mg g(-1) and 59 mg g(-1) at S1 and S2 respectively, while the life cycle impact assessment showed scores of -1 mg kg(-1) and -211 mg kg(-1) for Cr in agricultural soil and - 0.184 and - 38.7 for human health at S1 and S2 respectively in response to combined SiF + SiBC application, thus indicating the environment implication of Si nanoparticles and its biochar in ameliorating Cr toxicity in different environmental perspectives.

In modern industries, rare earth elements (REEs) are considered as essential metals and invaluable natural resources. Ion -adsorption deposits (IADs) are repositories of REE in the weathering crust soils, in which REEs are adsorbed on clay minerals. In the last few decades, the mining of REEs from IADs has caused substantial environmental damage owing to the overuse of leaching agents for the desorption and transport of REEs in weathering crust soils. These environmental issues have sparked extensive research interest in modeling REE transport dynamics in weathering crust soils. Nevertheless, because current models treat REE adsorption and transport independently, they do not accurately describe REE transport dynamics. Therefore, in this study, a unified workflow that synergizes adsorption and transport dynamics is proposed to predict REE transport. The adsorption of REEs on IADs was found to follow the Freundlich isotherm with the coefficient of determination exceeding 0.9826. The adsorption capacities of La 3+ , Sm 3+ , Er 3+ , and Y 3+ reach 1.3127, 1.4423, 1.5793, and 1.1061 mg g -1 at 300 ppm, respectively. For the breakthrough curve, an advection - dispersion - adsorption - eq- uation (ADAE) model was developed and utilized to accurately and reliably predict REE transport dynamics in soil columns. It was found the saturation time of REEs in soils is 39.22, 44.15, 50.64, and 32.17 h, respectively at 2 mL min -1 and decreased with the increase of flow velocity. The upper and lower limits of REE transport are ADAE-Freundlich and ADAE-Toth. More importantly, the model was applied to simulate REEs transport in fieldscale weathering crusts over 100 years and predict REE accumulation in the highly weathered layered, which is found in natural weathering crusts. The qualitative prediction of REE transport dynamics in weathering crusts may help fundamentally lower the usage of leaching agents and mitigate concomitant the environmental impacts of mining.

This paper presents a new and rigorous method for simulating thermo-elasto-plastic responses of soil during the cylindrical cavity expansion process under undrained conditions. The soil is modeled by a modified nonisothermal unified hardening model, which can properly consider thermal effects on mechanical responses, thermally induced excess pore water pressure as well as the overconsolidation characteristics. The temperaturedependent governing equations are derived by combining equilibrium equations and constitutive relations. New solution algorithms are developed to solve governing equations and update temperature -related parameters during the expansion process. Two typical scenarios, one is cavity expansion under different temperatures and another is temperature variation after expansion, are simulated. The proposed computational approach is validated through comparisons with results obtained from Abaqus numerical simulations, non -isothermal analyses, and experimental data. As demonstrated by extensive parametric studies, the proposed computational approach can reasonably capture the influence of temperature on cavity expansion, which can be further applied, modified, and developed for various industrial and geophysical problems involving thermoplastic soils.

The seasonal movement of the zero-degree isotherm across the Southern Ocean and Antarctic Peninsula drives major changes in the physical and biological processes around maritime Antarctica. These include spatial and temporal shifts in precipitation phase, snow accumulation and melt, thawing and freezing of the active layer of the permafrost, glacier mass balance variations, sea ice mass balance and changes in physiological processes of biodiversity. Here, we characterize the historical seasonal southward movement of the monthly near-surface zero-degree isotherm latitude (ZIL), and quantify the velocity of migration in the context of climate change using climate reanalyses and projections. From 1957 to 2020, the ZIL exhibited a significant southward shift of 16.8 km decade(-1) around Antarctica and of 23.8 km decade(-1) in the Antarctic Peninsula, substantially faster than the global mean velocity of temperature change of 4.2 km decade(-1), with only a small fraction being attributed to the Southern Annular Mode (SAM). CMIP6 models reproduce the trends observed from 1957 to 2014 and predict a further southward migration around Antarctica of 24 +/- 12 km decade(-1) and 50 +/- 19 km decade(-1) under the SSP2-4.5 and SSP5-8.5 scenarios, respectively. The southward migration of the ZIL is expected to have major impacts on the cryosphere, especially on the precipitation phase, snow accumulation and in peripheral glaciers of the Antarctic Peninsula, with more uncertain changes on permafrost, ice sheets and shelves, and sea ice. Longer periods of temperatures above 0 degrees C threshold will extend active biological periods in terrestrial ecosystems and will reduce the extent of oceanic ice cover, changing phenologies as well as areas of productivity in marine ecosystems, especially those located on the sea ice edge.

Although non-isothermal tests are important for many applications in geotechnical engineering, there is no standard for conducting such tests and interpreting the resulting data. This paper describes the development of a temperature-controlled triaxial apparatus, focussing on its thermal performance, and discusses relevant protocols to perform and interpret hydraulic conductivity tests on granular materials at different temperatures. With the aid of thermal cameras, hot spots on the surface of the equipment and instruments were identified. Subsequent modifications to minimise and mitigate heat reaching volume gauges and pore water pressure transducers were introduced. After modifications to reduce the system's intrinsic head losses, the thermal expansion of the system proved to be significant and needed to be accounted for avoiding overestimation of thermally-induced mechanical strains. The addition of a new probe at the centre of the specimen allowed the characterisation of the temperature field within the system and specimen, as well as assisting with the identification of thermal equilibrium. Significant drops in temperature were flagged by this probe, though these proved to be unimportant in terms of hydraulic conductivity. The use of the average temperature for each pressure step is advised when a specimen probe is available. Alternatively, the use of target temperatures can be chosen, leading to minor underestimations of the intrinsic permeability.