This study investigates the effects of thermal treatment on the mechanical behavior of highly compressible Pak Phanang clay, a soft soil with low strength that typically requires advanced ground improvement methods. Heating is considered a promising technique for enhancing foundation stability, particularly for critical infrastructure. The research focuses on the thermo-mechanical behavior of the clay, emphasizing consolidation and solidification processes that influence load-bearing capacity. Isotropically consolidated undrained triaxial tests were conducted at temperatures of 30 degrees C, 40 degrees C, 50 degrees C, and 60 degrees C with over-consolidation ratios (OCR) of 1, 2, 4, and 8. The results showed that increasing temperature significantly enhanced both peak deviator stress (qu\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${q}_{u}$$\end{document}) and the secant Young's modulus (E50\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${E}_{50}$$\end{document}), with a strong linear correlation: E50=108.70xqu\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${E}_{50}=108.70\times {q}_{u}$$\end{document}. Dry density increased and organic matter content slightly decreased under thermal treatment, particularly in normally consolidated clay. Excess pore water pressure (EPWP) increased linearly with temperature across all OCR values. Consolidation volume change also increased with temperature but decreased as OCR rose. The coefficient of consolidation (Cv\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${C}_{v}$$\end{document}) improved with temperature, leading to faster consolidation, especially in normally consolidated specimens. The coefficient of permeability (k\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$k$$\end{document}) increased with temperature but declined with higher OCR, with k rising by 14.6%-24.2% from 30 degrees C to 60 degrees C in normally consolidated samples. Predictive models for qu\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${q}_{u}$$\end{document} and k\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$k$$\end{document} based on temperature and OCR demonstrated high accuracy. Overall, the findings provide a reliable understanding of the thermal-mechanical response of this clay type, supporting its application in temperature-assisted ground improvement.

In existing studies, most slope stability analyses concentrate on conditions with constant temperature, assuming the slope is intact, and employ the Mohr-Coulomb (M-C) failure criterion for saturated soil to characterize the strength of the backfill. However, the actual working temperature of slopes varies, and natural phenomena such as rainfall and groundwater infiltration commonly result in unsaturated soil conditions, with cracks typically present in cohesive slopes. This study introduces a novel approach for assessing the stability of unsaturated soil stepped slopes under varying temperatures, incorporating the effects of open and vertical cracks. Utilizing the kinematic approach and gravity increase method, we developed a three-dimensional (3D) rotational wedge failure mechanism to simulate slope collapse, enhancing the traditional two-dimensional analyses. We integrated temperature-dependent functions and nonlinear shear strength equations to evaluate the impact of temperature on four typical unsaturated soil types. A particle swarm optimization algorithm was employed to calculate the safety factor, ensuring our method's accuracy by comparing it with existing studies. The results indicate that considering 3D effects yields a higher safety factor, while cracks reduce slope stability. Each unsaturated soil exhibits a distinctive temperature response curve, highlighting the importance of understanding soil types in the design phase.

Particle size distribution (PSD) of coral sand is a critical factor that influences the mechanical properties at the coral sand-geogrid (CS-GG) interface, which is affected by both particle breakage and various temperatures. However, relevant researches are scarce currently. This study conducts a series of large-scale interface shear tests on coral sand with three PSD ranges (0.25 similar to 1mm, 1 similar to 2mm, and 2 similar to 4mm) at varying temperatures (5 degrees C similar to 80 degrees C). Experimental results demonstrate that the IB value at the CS-GG interface ascends and then descends with the increase of PSD from 20 degrees C to 40 degrees C. The IB value at the interface descends and then ascends with the increase of PSD from 60 degrees C to 80 degrees C; The PSD curves at the interface indicate that the particle breakage degree of coral sand increases with rising temperature (5 degrees C similar to 40 degrees C); The larger PSD of coral sand, the smaller fractal dimensions (D) of the interface; A mathematical formulation of the relationship between the relative breakage rate (Br) and the D value at interfaces is presented, which considers temperature effects; The relationship between the total input energy (E) and the Br value has been expressed by empirical formulations with different PSD ranges, where the fitting curve for 2 similar to 4 mm coral sand exhibits a hyperbolic pattern.

Stiff clay exists widely in the world, but its significant time- and temperature-dependent mechanical features have not been fully modeled. In the context of fractional consistency viscoplasticity and bounding/subloading surface theory, this study proposes a novel nonisothermal fractional order two-surface viscoplastic model for stiff clays. First, by proposing a generalized plastic strain rate, the isotach viscosity is modified and extended to both over-consolidated and nonisothermal conditions that take into consideration the effects of temperature and OCR on thermal accelerated creep. Then, two strain rate and temperature-dependent yield surfaces are proposed with isotropic and progressive hardening rules to consider thermal collapse, strain rate effects, and smooth transition from elastic to viscoplastic behaviors. Next, the stress-fractional operator of the loading surface, according to the principle of fractional consistency viscoplasticity, is introduced to describe the nonassociativity of stiff clays. Finally, the predictive ability of the model is validated by simulating triaxial tests on Boom clay with various stress paths considering the temperature- and time-dependent features of stiff clays.

Principal stress rotation (PSR) significantly affects the cyclic behaviour of subgrade soil. Previous studies on PSR have been generally limited to saturated and isothermal conditions despite subgrade soil experiencing daily and seasonal variations in temperature and suction. This study incorporated temperature- and suction-controlled units into existing hollow cylinder apparatus to conduct cyclic shear tests, both with and without PSR, while maintaining identical cyclic deviatoric stress. The study considered different temperatures (5 degrees C, 20 degrees C, and 40 degrees C) and suctions (0, 10, and 30 kPa). The permanent strain increases and resilient modulus decreases as temperature rises and suction decreases. Furthermore, the incorporation of PSR results in increased permanent strain and decreased resilient modulus, with these changes being influenced by temperature and suction. At zero suction, the permanent strain increases by 130% and 230% at 5 degrees C and 40 degrees C when PSR is incorporated. As suction increases to 10 kPa, these values are 50% and 80%. These coupled effects are likely due to the decrease in the overconsolidation ratio (OCR) with increasing temperature and decreasing suction, with PSR effects being more pronounced at lower OCRs. Furthermore, a new semi-empirical equation was proposed to model these coupled effects on resilient modulus, a critical parameter in pavement design.

The risk of geohazards associated with frozen subgrades is well recognized, but a comprehensive framework to evaluate frost susceptibility from microstructural characteristics to macroscopic thermo-hydro-mechanical (THM) behaviors has not been established. This study aims to propose a simple framework for quantitatively assessing frost susceptibility and compressibility in frozen soils. A systematic THM model was devised to predict heat transfer, soil freezing characteristics, and stress states in frozen soils. Constant freezing experiments and oedometer compression tests were performed on bentonite clays under varying temperatures (-5 degrees C, -10 degrees C, and -20 degrees C) and stress levels to validate the proposed model. Additionally, soil electrical conductivity measurements were employed to assess the temperature- and stress-dependent volumetric and mechanical properties of frozen soils. The model used Fourier's law to compute the transient soil temperature profile and estimated the volume change and stress states based on the soil freezing characteristic curve. Experimental results showed that frost heave of bentonite reached between 9.0% and 26.6% of axial strain, which was largely predicted by the proposed model. It also demonstrated that the frost heave was mainly attributed to the fusion of the porewater. Additionally, the preconsolidation pressure of frozen soils exhibited a rapid increasing trend with decreasing temperature, which was explained by the temperature-dependent ice morphology in the soil interpore. Furthermore, the findings also demonstrated a remarkable sensitivity in the electrical conductivity in response to the soil temperature during the frost heave process and the stress state under the loading or unloading path.

Frictional heating -induced excess pore water pressure is a significant factor contributing to the rapid movement of landslides. Although some studies have explored the thermal effects on fully saturated soil slopes, this study focuses on unsaturated soils and employs a thermo-hydro-mechanical (THM) coupled material point method (MPM) to simulate large deformation problems involving frictional heating. The THM coupling effects are accounted for by adopting a void ratio and temperature -dependent soil water retention curve (SWRC) and permeability function, and by considering the influence of void ratio and degree of saturation on thermal conductivity. The mechanical behaviour incorporates unsaturation effects, as well as thermal strain and strain hardening/softening. The MPM simulations are validated against experimental and analytical results, and parametric studies are conducted to investigate the influence of frictional heating on landslide mobility across different soil types and initial moisture conditions. The results indicate that the effects of frictional heating on the mobility of landslides involving soil with higher water retention capacity are less pronounced. For a given soil, when the initial water content is relatively low, the increase in landslide displacement caused by frictional heating becomes less significant as the water content increases. However, the opposite trend occurs when the soil is close to saturation.

Polyethylene has temperature dependent properties. As a thermoplastic material, it softens on heating and hardens on cooling. This behavior affects the contact surface areas of materials made out of polyethylene, such as geomembranes, adjacent to other materials. Interface strength properties depend on the contact area and stress at the interface. Since the soil-geomembrane interfaces are relatively weak and potentially form the critical failure planes, modeling temperature dependent soil-polyethylene contact surfaces is important. A theoretical model to determine soil-polyethylene contact areas was developed during this study and presented in this paper.

Infrastructure in cold regions is vulnerable to the potential degradation of permafrost under a warming climate. Meanwhile, the accumulation of meteorological data and the refinement of AOGCMs in recent years have improved the confidence in future global air temperature predictions. A reliable scheme is now desired that converts these climate predictions into future geocryological predictions relevant to geotechnical engineering and risk assessment. This paper describes a multidisciplinary approach that provides a first estimate of transient ground responses to climate change on a regional basis. The scheme integrates locally adjusted AOGCM climate predictions, regional geological assessments, non-linear thermal finite element analysis and digital elevation models derived from remote sensing data. The practical application of the approach is demonstrated through predictions made of the geocryological changes expected between 1940 and 2059 in a Siberian region. The paper presents results from one sampled area where discontinuous permafrost is present beneath rolling hills terrain. It is shown that elevation, vegetation and local geological variations all affect the development of permafrost, with important implications for infrastructure design and operation. A range of useful geocryological maps can be output from the procedure, including temperature at the active layer base, permafrost table depth, and ground temperature at any desired depth. It is shown that the permafrost model's predictions for present-day conditions agree well with existing geocryological maps. An illustrative example of how simple geohazard maps may be prepared from the output is also provided.