In the Chinese Loess Plateau, interbedded loess–paleosol sequences constitute a typical geological setting for rainfall-induced landslides. The contrast in seepage behavior between loess and paleosol is an important triggering factor for landslides. This study develops a hydro-mechanical coupling framework for loess–paleosol slopes characterized by layered heterogeneity in permeability structure. Within this framework, a unified dual–single permeability moisture-migration model is established to capture nonequilibrium seepage in loess and the single-permeability behavior of the paleosol. The coupled analysis incorporates the hydro-mechanical effects of pore-water pressure and soil unit weight. A loess–paleosol slope in Yan'an City, China, is taken as the study site to investigate the hydraulic response and stability evolution under two regionally representative rainfall scenarios. The results are further discussed through comparative analysis and actual landslide cases. The paleosol layer markedly impedes preferential flow in the overlying loess, facilitating the rapid development of perched water along the loess–paleosol interface. This results in spatial discontinuities in pore-water pressure across the interface, thereby inducing strain concentration at the interface. Under high-intensity, short-duration rainfall, the factor of safety decreases more substantially, and the interface-controlled failure mode is more pronounced than under low-intensity, long-duration rainfall.

With the continuous promotion of engineering construction in western China, it is increasingly acknowledged that the frequency and harmfulness of deformation and destabilisation of anti-dip rock slopes are comparable to those of dip rock slopes. Due to the characteristic "no pre-existing weak planes" of anti-dip rock slopes, the cumulative deformation and fracture of rock strata result in slope destabilisation. Focusing on the evolution chain "deformation of rock strata - damage (or fracture) of rock strata - slope destabilisation", this study investigates the mechanisms of deformation and destabilisation of anti-dip rock slopes through a numerical simulation method. For the anti-dip rock slope with a large dip angle of the rock strata, the significant stress characteristic of the rock strata "tension near the upper surface - compression near the lower surface" results in obvious flexural deformation and tensile fracture. The slope undergoes long-term damage and eventually occurs destabilisation. This stress characteristic gradually diminishes and eventually vanishes with decreasing dip angle of the rock strata. The resulting initiation mode of slope destabilisation transitions from tensile fracture to compressive fracture of the rock strata at the slope toe. Meanwhile, the destabilisation mode of slopes transitions from toppling type to sliding type, and the corresponding failure boundary transitions from dual stage toppling-fracture type to multistage sliding type. Moreover, the combined effects of the slope angle and the dip angle of the rock strata are discussed during the process of deformation and destabilisation of anti-dip rock slopes.