Freeze–thaw deformation in frost-susceptible soils couples heat transfer, phase change, water redistribution and irreversible thaw deformation. This study develops an axisymmetric Voronoi–Delaunay lattice framework with a finite-element-analysis-program (FEAP)-compatible residual–tangent organization, embedded displacement-jump histories and a bounded temperature-dependent creep law. Delaunay edges carry normal–shear interactions, while a circumcentric dual supplies transport faces and storage volumes. The global benchmark implementation combines apparent-heat-capacity heat transfer, a reduced total-water redistribution equation and fixed-reference small-strain lattice mechanics; it is not a complete Darcy-flow, effective-stress or discrete ice-lens formulation. Verification against radial conduction, Stefan-front propagation and confined compression produced errors of 1.45%, 3.53% and 5.88%, respectively. First-cycle heave and thaw-settlement endpoints from one closed Kieler Förde test and six independent open-system tests were used for case-level calibration. The calibrated model reproduced those endpoints with a median absolute percentage error of 0.36%. The subsequent Kieler Förde cycle trend was assessed without further endpoint calibration, and the FEAP jump–creep enrichment retained a median endpoint error of 3.03% without re-optimisation. Predicted temperature, ice fraction, total water, pressure proxy and displacement fields are reported as model outputs because co-registered water-content profiles, pore pressures and freezing-front positions were not available for every case. Four CPU workers produced a measured 3.25-fold batch speedup; an optional GPU sparse-solver route is supplied with deterministic CPU fallback. The framework is therefore intended for rapid laboratory-scale displacement assessment, while finite-strain kinematics and fully coupled ice-lens poromechanics remain future developments.
Drilling-mud sumps, used for the disposal of drilling fluid (saline mud and drill cuttings) from exploratory oil and gas wells in northern regions, are vulnerable to climate warming driven permafrost thaw and subsequent mobilization of once-frozen contaminants, including freezing point depressants such as salts. Overall, the long-term contaminant transport and thermal behavior of sumps in the face of climate change is not well understood. One-dimensional freeze-thaw column experiments packed with sand were conducted to quantify thermal response, advective-driven effluent discharge, and examine the interactions between contaminant concentration (0, 10, 100 g L−1 KCl) and thawing rates. Sand columns were subject to 1D freezing under saturated conditions followed by 1D thawing under gravity drainage to allow for effluent discharge through connected pathways. Instrumentation monitored soil temperatures along the column length as well as effluent discharge rate and concentration. Thermally, the experiments quantified the magnitude of freezing point depression and salt precipitation at the eutectic temperature. Initial effluent discharge salinity concentrations were up to three times greater than the initial concentration and significant contaminant mobilized below theoretical freezing point temperatures, revealing possible mobility mechanisms for saline porewater. This work provides a foundation for further research and understanding of sumps, which must include consideration of both freezing point depression and aqueous-to-solid phase change at the eutectic point, allowing for better monitoring, modelling, mitigation and management of both sumps and other contaminated sites in northern regions.
Snow is a key component of the cryosphere in the Himalaya-Karakoram-Hindukush (HKH) region, strongly influencing regional hydrology and climate; this study examines the temporal variability of Snow Cover Area (SCA) and Snowline Altitude (SLA) in response to in-situ observations using the improved MOYDGL06 snow dataset. To ensure robust trend detection in serially correlated data, we applied Trend-Free Pre-Whitening (TFPW) prior to conducting the Mann-Kendall (MK) test and Sen's slope estimator. Results, shown as monthly trends, revealed a statistically significant decline in SCA in the Hindukush during January (p = 0.03; Sen's slope: −65.14 km2/yr−1). Conversely, the Himalaya and Karakoram generally exhibited non-significant decreasing trends. Temperature and precipitation exhibited heterogeneous trends across temporal scales, with both significant and non-significant changes. Mean SLA ranged from 1832 ± 226 m in February to 5466 ± 249 m in August in the Himalaya, from 1689 ± 222 m in February to 4377 ± 161 m in August in the Hindukush, and from 2542 ± 332 m in January to 4583 ± 141 m in August in the Karakoram. Trends indicated that monthly SLA in the Himalaya and Hindukush exhibited significant upward trends in January (p = 0.04; 33 m/yr−1; p = 0.02; 23 m/yr−1, respectively), while non-significant upward trends were observed at the monthly, seasonal, and annual scales. Furthermore, SCA was strongly negatively correlated with SLA and temperature, whereas relationships with precipitation varied regionally, highlighting spatiotemporal cryospheric variability across the UIB.
