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Experimental and analytical researches have shown that the use of the bottom air-deck blasting improves fragmentation and reduces toe problems. In this research modelling of bottom air-deck blasting in a single hole, using numerical methods was taken into account. Considering the advantages of the Smoothed Particle Hydrodynamics (SPH) method, this method was used for modelling. In order to reduce the runtime of the process, the SPH–FEM coupled method was applied, using LS-DYNA software. To validate the modelling, the results of an experimental modelling of a single blast hole, in Barre granite was used. The results have shown that at the start of detonation, as the first free face is the bottom air-deck, hence, the blasting shock wave and explosive products move toward the air-deck area at a speed of 2.5 km/s and pressure on the wall of the blast hole in the air-deck area is more than the one at the starting point of detonation. Also, in conventional blasting, initial induced pressures are more than ones induced by air-deck blasting, but regarding the high attenuation of waves in conventional blasting, the applying time of pressures is very small. In bottom air-deck blasting, although the level of initial pressures are low, however, multiple impacts of blast waves in the air-deck area can transform compressive stress to tensile stress and produce higher and longer duration waves. These phenomena can contribute to an increase in the creation of fractures and improve the fragmentation at the bottom of the blast hole. [ABSTRACT FROM AUTHOR]

Flow slide is a flow-type landslide, which has high mobility and is destructive to the downstream infrastructures and buildings. In this study, a numerical method is presented to simulate the runout process of flow slide, and the interactions between flow slide and buildings on three-dimensional terrain considering the destruction process. In this proposed method, the flow slide is simulated by smoothed particle hydrodynamics (SPH) and the buildings are simulated by the finite element method (FEM). A node-to-surface contact algorithm is adopted to transfer displacements and contact forces between the flow slide and the buildings. An element erosion algorithm is adopted to simulate the destruction process. The method is validated using an analytical solution to dam break problem and the experimental results in two flume tests. A catastrophic flow slide involving building destruction is then simulated to further test the model performance. The flow depth, flow velocity, deposition area, and building damage degree are all reasonably simulated. The typical destruction process of buildings and patterns of the flow slide are also identified. The method will contribute to a better understanding of flow-structure interactions and is a promising tool for hazard analysis and mitigation. [ABSTRACT FROM AUTHOR]