To investigate the effects of impact and static compaction methods on the mechanical properties and crack evolution of rock-like materials with varying particle sizes. Uniaxial compression tests combined with Digital Image Correlation (DIC) technology were conducted on specimens of two aeolian sand gradations (0.075–0.18 mm and 0.22–0.5 mm) and one quartz sand gradation (0.22–0.5 mm). The study focused on elastic modulus, peak strength, stress-strain behavior, failure modes, surface deformation fields, crack propagation paths, and strain evolution at characteristic points under both compaction methods. Finally, the microstructure of specimens was analyzed and compared with natural rock analogs. Key results include: (1) At an identical density of 1.82 g/cm³, static-compacted specimens of fine-grained aeolian sand (0.075–0.18 mm) exhibited higher elastic modulus and peak strength compared to impact-compacted counterparts, whereas inverse trends were observed for coarse-grained aeolian sand (0.22–0.5 mm) and quartz sand specimens; (2) Under equivalent compaction energy (254.8 J), the hierarchy of mechanical performance was: quartz sand > coarse-grained aeolian sand > fine-grained aeolian sand; (3) Static-compacted specimens predominantly failed through tensile splitting, while impact-compacted specimens exhibited shear-dominated failure modes; (4) DIC full-field strain mapping revealed rapid propagation of primary cracks along pre-existing weak planes in static-compacted specimens, forming through-going tensile fractures. In contrast, impact-compacted specimens developed fractal strain field structures with coordinated evolution of shear bands and secondary tensile cracks; (5) Microstructural comparisons showed that static-compacted fine-grained aeolian sand specimens exhibited root-like structures with high porosity, resembling weakly consolidated sedimentary rocks. Impact-compacted coarse-grained aeolian sand specimens displayed stepped structures with dense packing, analogous to strongly cemented sandstones.

Vegetation restoration can reduce soil erosion and improve soil stability on erosion-prone slopes, but the contrasting roles of herbaceous and shrub species in surface erosion resistance and subsurface reinforcement remain unclear. This study compared two herbaceous species, Melilotus officinalis (L.) Pall (MOP) and Suaeda glauca (Bunge) Bunge (SGB), and two shrub species, Alhagi camelorum Fisch. (ACF) and Nitraria tangutorum Bobrov (NTB), with bare soil (CK) as the control. Soil detachment capacity (Dc), root–soil shear strength, root traits, and soil properties were measured using planting experiments, flume scouring tests, and direct shear tests. Compared with CK, the vegetation treatments showed lower bulk density and higher total porosity and water-stable aggregates content, while soil organic matter exhibited differences among treatments. Herbaceous species developed dense fine roots in surface soil, whereas shrubs had deeper, coarser root systems. Vegetation significantly increased root–soil shear strength, mainly by increasing cohesion; herbs provided stronger surface reinforcement, whereas shrubs maintained more stable reinforcement at depth. All vegetation treatments significantly reduced Dc, and MOP showed the best overall anti-erosion performance. Random forest analysis further showed that root traits dominated Dc variation, accounting for 84.9% of total variable importance, with root length density and root surface area density as the leading factors. A regression model based on shear stress, total porosity, bulk density, and root length density predicted Dc well (R² = 0.86, NSE = 0.65, RMSE = 0.083). These findings support site-specific vegetation selection: herbs for surface erosion control, shrubs for slope-stability concerns, and shrub–herb combinations where both risks coexist.