Spatial Modeling for Debris Flow Analysis

Abstract

Debris flows are among the most hazardous natural phenomena in mountainous regions, often resulting in severe infrastructure damage and loss of life. The study examines the physical and rheological characteristics of debris-flow material obtained in the area of a dam that traps debris in Almaty, Kazakhstan. To identify the grain size distribution, atterberg limits, specific gravity, viscosity, and yield stress, laboratory tests were carried out. The laboratory results indicated that the investigated material is predominantly coarse-grained with a limited proportion of fine particles. Rheological analysis demonstrated behaviour consistent with a Bingham-type fluid, where both yield stress and viscosity decreased with increasing water content. Numerical analyses using FLO-2D showed that debris-flow propagation in the Kumbelsu River basin was strongly controlled by local topography and material properties, while increasing discharge led to higher maximum flow depth and velocity. The simulations also showed that FLO-2D is useful for representing general flow direction, depth, velocity, and hazard distribution, although discrepancies with the historical event remained because of limitations related to surge waves, DEM differences, and rheological input data.