In this study, landslide risk assessment was conducted in the Renhe District, Panzhihua City, China. Firstly, based on 190 landslide points and 10 influencing factors, the landslide hazard was assessed using three models: random forest (RF), eXtreme Gradient Boosting (XGBoost), and Tabular Prior-data Fitted Network (TabPFN). The results indicate that the RF and XGBoost models exhibit comparable performance, both demonstrating strong generalization and accuracy, with the RF model achieving superior generalization, as evidenced by an area-under-the-curve (AUC) value of 0.9471. While the AUC value of TabPFN is 0.9243, indicating higher accuracy, it also poses a risk of overfitting and is therefore more suitable for applications involving small sample sizes and the need for rapid responses. The vulnerability assessment utilized the Analytic Hierarchy Process (AHP) to determine the weights of four disaster-bearing bodies, with sensitivity analysis revealing that road type was the most sensitive vulnerability factor. Finally, the landslide risk-assessment map of the Renhe District was produced by integrating the landslide hazard assessment map with the vulnerability assessment map. The findings indicate that the high-risk zones comprised 2.08% of the research region, which includes three principal train stations and necessitates enhanced protective measures. The medium-risk zones comprise 34.23% of the total area and are scattered throughout the region. It is important to enhance local capabilities for landslide monitoring and early warning systems. Relevant conclusions can provide a significant reference for landslide disaster prevention and mitigation work in the Renhe District and help ensure the safe operation of public transport infrastructure, such as railway stations and airports in the district.

High-position landslide debris flows triggered by earthquakes frequently occur in the southwest mountainous areas of China. The research on the high-speed and long-distance movement characteristics and mechanisms of such landslide debris flows is crucial for disaster early warning and prevention. This study focuses on the high-position rockfall-landslide debris flow in Luding County, Sichuan Province, and uses a combination of field investigation, rheological testing, and numerical simulation to reveal the rheological properties and catastrophic mechanisms of landslide debris flows under seismic loading. The results show that with increasing water content, the storage modulus (G′) and loss modulus (G′′) of the debris-flow soil significantly decrease, and shear-thinning is more pronounced at low water contents. High-frequency vibration (>10 Hz) suppresses the solid–liquid transformation of the soil, while low-frequency vibration (<1 Hz) accelerates its liquefaction. As frequency increases, the dependence of yield shear strain on water content decreases significantly. Also, as water content decreases, the dependence of yield shear strain on frequency lessens. Numerical simulation using RAMMS (Rapid mass movement simulation) shows a high overlap rate of 92.3% between the simulated debris-flow movement and the actual disaster-affected area, confirming the model′s reliability. The study indicates that seismic loading reduces the shear strength of the soil, increases pore-water pressure, and causes particle rearrangement, thus lowering the critical conditions for debris-flow initiation. The findings provide a theoretical basis for early warning and prevention of high-position landslide debris flows triggered by earthquakes.

Due to the loose and non-cohesive nature of sandy soil, road subgrade slopes in sandy regions are highly unstable, often experiencing adverse geological disasters such as shallow landslides and uneven settlement. To mitigate these hazards and promote sustainable development, vegetation root systems are frequently employed for slope stabilization. This paper investigates the reinforcing efficiency of roots in sand matrix via single-root tensile tests and mixed-level orthogonal direct shear tests. The tensile tests reveal that the peak tensile force (F) exhibits a robust linear increase with root diameter (d) (F = 26.81d − 11.33, R2 = 0.80), whereas the ultimate tensile strength (RM) decays non-linearly via an inverse power function. Orthogonal direct shear tests demonstrate that root orientation is the governing factor controlling both composite shear strength and apparent cohesion, exhibiting a hierarchical influence priority of Orientation > Quantity > Diameter. Specifically, root inclusions primarily enhance the ultimate shear strength by increasing the cohesion, with negligible variation in the internal friction angle. The optimal root configuration for maximizing overall shear strength adopts 1.5 mm-diameter roots, a root number of 6, and an inclined orientation. Mechanistically, shear strength enhancement of the composite arises from a cooperative effect of interface friction, axial tensioning/anchoring, and structural interlocking, forming an anisotropic, parameter-specific system rather than a uniform strength upgrade. Thicker roots, under inclined or vertical arrangements, actively mobilize their tensile capacity (F) to resist shearing force. Conversely, three-dimensional vertical-horizontal (cross) networks maximize spatial confinement and structural interlocking, selectively optimizing the apparent cohesion to a peak value of 15.67 kPa. These findings provide a mechanical reference and root-architecture optimization strategies for slope stabilization projects in arid environments.