In global cold regions and seasonal frozen soil areas, frost heave failure of rock slopes severely endangers infrastructure safety, particularly along China’s Sichuan–Tibet and Qinghai–Tibet Railways. To address this, a meshless numerical model based on the smoothed particle hydrodynamics (SPH) method was developed to simulate progressive frost heave and fracture of water-saturated fissured rock masses—its novelty lies in avoiding grid distortion and artificial crack path assumptions of FEM as well as complex parameter calibration of DEM by integrating the maximum tensile stress criterion (with a binary fracture marker for particle failure), thermodynamic phase change theory (classifying fissure water into water, ice-water mixed, and ice particles), and the equivalent thermal expansion coefficient method to quantify frost heave force. Systematic simulations of fissure parameters (inclination angle, length, number, and row number) revealed that these factors significantly shape failure modes: longer fissures and more rows shift failure from strip-like to tree-like/network-like, more fissures accelerate crack coalescence, and larger inclination angles converge stress to fissure tips. This study clarifies key mechanisms and provides a theoretical/numerical reference for cold region rock slope stability control.

This study investigates upper-reservoir dam-axis siting in pumped-storage hydropower projects, where cut–fill balance and construction cost are critical under complex terrain conditions. Existing approaches still rely heavily on manual interpretation or static GIS-based analysis and therefore do not adequately optimize dam-axis geometry or earthwork balance. To address this limitation, we propose an Improved Adaptive Variable Neighborhood Search (IAVNS) algorithm that integrates high-resolution digital elevation model (DEM) data within a two-layer adaptive framework. The inner layer performs staged planar and elevation adjustments through adaptive neighborhood operators, whereas the outer layer conducts fitness-guided subregion migration to strengthen global exploration. Experiments on the Qiannan pumped-storage project show that IAVNS obtains layouts with improved cut–fill balance. In the 30-run benchmark comparison, IAVNS achieved a mean CFR of 1.31, which is close to, although slightly above, the upper bound of the adopted earthwork-balance reference interval. In the separate 20-run case-study analysis, the average storage-volume deviation was 0.13%, with run-level deviations ranging from $-1.39\%$ to $1.16\%$. In benchmark comparisons, IAVNS improves solution quality by 22.8% relative to the Genetic Algorithm (GA) and by 16.5% relative to classical Variable Neighborhood Search (VNS), while reducing convergence time by 49.5% and 27.4%, respectively. Sensitivity analysis further suggests that the framework remains locally robust under practically reasonable parameter perturbations, and the module-level ablation study indicates that the observed performance gains arise mainly from the problem-tailored search mechanisms for dam-axis siting rather than from a generic combination of metaheuristic components. Taken together, the case-study results, repeated-run comparison, sensitivity analysis, and ablation study support the use of IAVNS as a geometry-oriented decision-support framework for preliminary dam-axis design in terrain-sensitive hydraulic engineering applications.

Against the backdrop of global climate change and rapid urbanization, island cities face increasing compound-flood risks due to their fragmented topography and limited terrestrial space, yet cross-scale modeling and high-resolution exposure assessment for archipelagic environments remain insufficient. Taking Zhoushan City, China, as a case study, this research develops an integrated compound-flood multi-receptor exposure assessment framework combining cross-scale hydrodynamic modeling with high-resolution spatialization. For hazard assessment, a one-way sequential coupling of a parametric typhoon model, FVCOM, and LISFLOOD-FP was employed to simulate storm-surge, pluvial, and compound flooding at 50-, 200-, and 1000-year design levels. Model performance was evaluated using tidal-gauge observations, historical storm-surge records, remotely sensed historical inundation, and documented urban waterlogging locations. For exposure assessment, Random Forest-based dasymetric mapping was used to generate 30 m population and secondary- and tertiary-sector GDP datasets; primary-sector GDP was spatialized using a land-cover-based approach, and 3314 critical-infrastructure facilities were compiled across eight subsystems. The results reveal the following: (1) compound-flood inundation areas were 289.95, 424.93, and 513.31 km² under the 50-, 200-, and 1000-year design scenarios, respectively; (2) under the 1000-year compound scenario, 57.5% of the population, 51.3% of GDP, and 63.3% of critical infrastructure were exposed; (3) infrastructure exposure showed strong subsystem heterogeneity, with coastal facilities having the highest exposure ratio (76%) and emergency-rescue facilities reaching 65.3%; (4) sector-disaggregated GDP exposure revealed substantial economic-geographic differences among districts/counties, highlighting the need for differentiated adaptation strategies. The proposed framework provides spatially explicit information to support differentiated coastal adaptation planning and is transferable to other archipelagos and small island cities with similar data constraints.