Hydrodynamic and topography based cellular automaton model for simulating debris flow run-out extent and entrainment behavior.

As for late, studies have indicated that cellular automaton (CA) models are among the most effective solutions for simulating the extent of debris-flow run-out. However, it is currently difficult to effectively simulate both the inundated area and the erosion pattern of the debris flow process. This difficulty is caused by the lack of detailing regarding debris flow hydrodynamics as the primary concern of most CA-based models is the topographic gradient of the gully. In this study, we propose a two-dimensional Monte Carlo simulation-based CA model with hydrodynamic methods describing debris-flow behavior to address these problems. Herein, a topography function concerning slope gradient and bed roughness, and a persistence function regarding flow inertia, are combined to improve the flow routing algorithm for better determining the run-out extent of debris flow. Hydraulic links and discharge exchange between neighboring cells using sink-filling approach, as well as the bed sediment entrainment function, are incorporated into the CA model to describe the mass migration process along the flow path. To verify the performance of our proposed model, we further select the 2010 Yohutagawa debris flow event in Japan as a case study. The results indicate that the proposed model better simulates the complex dynamic process of debris flow.

Comprehensive analysis of landslide stability and related countermeasures: a case study of the Lanmuxi landslide in China.

We report on a comprehensive method for analyzing landslide stability and the mitigation effect of countermeasures in this paper. The proposed method is a combination of theoretical method and numerical method. To address the uncertainties of the soil strength parameters, the rational values of these parameters are comprehensively determined by the back-analysis result of the reliability method and the result by the quantitative method, as well as the in-situ geological test. To evaluate the slope stability, the limit analysis using the 2D upper bound method and the FEM simulation using strength reduction method are performed, respectively. In order to illustrate the presented method, the so-called Lanmuxi landslide in China is selected as a case study. Results demonstrated that the stress and strain majorly concentrated at the toe and crown of the slope. According to the analysis results, countermeasures consisting of anchor lattice beams, landslide piles, and cracks filling, are suggested to reduce the failure risk of the landslide. Effect assessment based on the FEM analysis verifies the feasibility and effectiveness of the recommended countermeasures.