Institute of Rock and Soil Mechanics

In geotechnical engineering, the mechanical behavior of calcareous soils (CS) is significantly influenced by particle breakage and the resulting change in shape morphology. This study focuses on understanding the characteristics of particle breakage and shear strength of CS by conducting consolidated and drained triaxial compression tests using different initial relative densities and particle size ranges. The morphological parameters of individual particles were quantified before and after each test by using both dynamic image analysis (DIA) and mechanical sieving analysis. The relationship between the deviatoric stress and the axial strain exhibited strain-softening behavior under an effective confining pressure <400 kPa, while the soil demonstrated a gradual transition to strain-hardening behavior with the increase in confining pressure. For CS specimens of initial particle size ranges of 2–5, 1–2, and 0.5–1 mm, the mean peak friction angles were roughly 37°, 39°, and 40°, respectively. The dilatancy angle increased linearly with the initial relative density but decreased linearly with the effective confining pressure. The CS exhibited apparent cohesion due to the particle interlocking effect. The DIA outcomes indicated that the frequency counts of particle sphericity, aspect ratio, and flatness both before and after the experiments closely followed a Gaussian distribution. The frequency counts of convexity after the tests, however, followed an exponential distribution. The overall shape of the CS particle evolved to a subspherical shape with a smoother particle surface after the shear process. The proposed DIA method proved to be accurate in quantifying particle breakage with irregular particle shapes.

Light-Burned Magnesia (LBM) activated Ground Granulated Blast Furnace Slag (GGBS) is established as a promising and robust binder for soil stabilization. However, its durability in saline environments subjected to freeze-thaw (F-T) cycles lacks systematic investigation. To validate its potential for subgrade engineering in seasonally frozen regions, this study evaluates the mechanical and microscopic properties of LBM-GGBS solidified saline soil under F-T cycling. The effects of LBM and GGBS on the unconfined compressive strength (UCS), permeability coefficient, Cl- leaching and microstructures of solidified saline soil after different F-T cycles (0, 2, 4, 6, 8, and 10) were examined. The results showed that increasing the LBM-GGBS content significantly enhanced the soil's resistance to F-T cycles. With a 12% LBM-GGBS content and a GGBS/LBM ratio of 7 (determined as the optimal mix proportion), the solidified soil reached a residual strength of 3MPa after 10F-T cycles, which was four times the strength required for the upper base layer of highway pavement subgrade. Microscopic analysis revealed that the LBM-GGBS solidified soil exhibited a dense structure with calcium silicate hydrate (C-S-H), magnesium silicate hydrate (M-S-H), hydrotalcite, and Kuzel salt as the primary reaction products. The formation of these hydration products significantly densified the structure, thereby increasing the strength and improving the F-T resistance of the solidified soil. Furthermore, ~ 75% of Cl- in the original saline soil could be stabilized even after multiple F-T cycles. These findings elucidate the micro-mechanism of chloride stabilization under freezing conditions and provide a robust theoretical foundation for utilizing LBM-GGBS to mitigate saline soil hazards in seasonally frozen regions.

The acid rain corrosion mechanism and apparent performance degradation of stone cultural relics are related to the safety of cultural relics, the complete preservation of historical information and the sustainable inheritance of cultural heritage. Limited by sampling, it is difficult to test and analyze limestone cultural relics under acid rain corrosion by traditional methods. In this study, nanoindentation technology suitable for micro-samples was adopted, combined with SEM, uniaxial compression testing, and image binarization analysis techniques. This approach enabled a cross-scale examination of morphological changes and mechanical property degradation patterns in limestone cultural relics. The results indicate that acid rain induces significant morphological damage to limestone artifacts. Furthermore, both their quality and macro-micro mechanical properties deteriorate as dissolution time increases, these changes stabilize after 1080 h. The deterioration law of macro-micro mechanical properties is consistent. These findings provide theoretical guidance for acid rain prevention measures in similar stone artifacts.

Surge waves generated by landslides can lead to catastrophic consequences, including severe economic losses and lose of life. This study invenstigates the surge waves induced by the Mogangling landslide triggered by the 1786 Moxi earthquake through a combination of numerical simulations and field surveys. A detailed field invenstigation was conducted to characterize the engineering geological features of the Mogangling landslide. Based on the point cloud data, a three-dimensional (3D) landslide model was constructed and used for numerical simulations. The landslide motion was simulated using a granular flow model, while wave propagation was modeled using the renormalisation group (RNG) turbulence model. These two models were coupled to analyze the genaration and evolution of the landslide-induced surge waves. The simulation results indicate that the peak sliding velocity of the landslide approached 20 m/s. As the landslide mass entered the Dadu River, a large landlside-dam formed, temporarily blocking the river and genrating intense surge waves. The peak water velocity increased to 30 m/s, and the maximum wave height reached 81.78 m, which is consistent with historical record-roughly 80 m. The surge waves propagated in a circular pattern toward the opposing riverbank. The findings provide insights for the risk assessment of landslide-induced surge waves.

Large-scale carbon capture, utilization, and storage (CCUS) is pivotal for global net-zero transitions, yet its deployment is constrained by suboptimal pipeline network designs that oversimplify techno-economic models, enforce rigid topologies, and computation bottlenecks. Here, we present a preferential-flow approach in porous and bioinspired algorithms that bridge microfluid dynamics and macroscale infrastructure design to address these bottlenecks. It mimics pore-scale preferential flow, or piping flow, in porous media, in which fluids naturally follow the least-resistance paths. This algorithm leverages the mathematical similarity between microscale hydraulics, pipeline flow, and cost models to facilitate cost-optimized network evolution. Nationwide simulations reveal that standalone CCUS projects in four coal-based energy and industrial sectors achieve 5.7 Gt/a at levelized costs of <$90/ton. In contrast, hub-and-spoke clusters reach 6.5 Gt/a under the same threshold in China. The resulting networks feature bimodal centroid-governed architectures that route carbon fluxes between emission sources and storage sinks while circumventing high-cost zones, with distinct regional signatures: radial configurations in northwestern basins, north–south corridors across southern China, multicentric layouts in the northeast, and land-ocean integrated west-to-east pathways in eastern regions. Validation in Ningxia demonstrates >80% emission reduction at <$50 per ton, outperforming current benchmarks. This framework advances CCUS infrastructure design through four key breakthroughs: enhanced physical fidelity by incorporating microscale flow phenomena; continuous-variable simulation capacity; 32k-grid computations completed in 5 min (compared to days for conventional approaches); and quantitative cost characterization via a novel “Carbon Reduction Matrix”. By reconciling principles of natural systems with macro-scale decarbonization imperatives, this scalable tool redefines CCUS design paradigms, providing a flexible and efficient pathway to accelerate global net-zero transitions.