Abstract: This study investigates the influence of many factors, specifically the strength parameters of geotechnical materials, on the run-out distance of flow-like landslides. Due to the limitations of field tests and laboratory experiments, strength parameters of soils usually exhibit significant spatial variability with different scales of fluctuation (SOF) in different directions, which is the anisotropy of SOF. Aiming at the influence mechanism of anisotropic SOF of the cohesion random field on the run-out distance of flow-like landslides, this study introduced the mid-point method based on the Cholesky decomposition to generate the anisotropic random field. The smoothed particle hydrodynamics (SPH) analysis method, combined with the Mohr-Coulomb failure criterion and the non-Newtonian fluid model, was used to simulate the sliding process and run-out distance of landslides. A stochastic analysis method for the flow-like landslide motion process was established within Monte Carlo simulation framework. Then, by simulating the Yangbaodi landslide and the horizontal strata model, the applicability of the SPH method and the random field discretization method was validated. Finally, a conceptual landslide case was constructed based on the topographic data of the Wangjiayan landslide that was triggered by the Wenchuan earthquake. The study discussed the movement process under the anisotropic SOF in the random field of cohesion and analyzed the probability distribution characteristics of run-out distances. The results show that an increase in the vertical fluctuation range results in a wider range of variation in run-out distance, and the sliding distances exhibit a discrete nature; on the premise that the cohesion parameter conforms to the lognormal distribution, the distribution of the run-out distance also conforms to the same lognormal distribution, which proves that the run-out distance distribution of flow-like landslides is closely related to the distribution characteristics of inputted parameters.

Key words: cohesion, scale of fluctuation, anisotropy, flow-like landslide, run-out distance, smoothed particle hydrodynamics (SPH), stochastic analysis