Simulation of Falling Rocks Using Two-Fluid Model

Rockfalls are considered to be very dangerous slope processes that can lead to serious consequences. These processes occur in mountain territories. Investigation of rockfalls motion to estimate affected area and hazard effects is very important. Mathematical and computer modeling methods allow to estimate the influence of the slope parameters (such as the slope angle, the slope height, the slope shape, the volume of the falling rock mass, etc.) on the runout after rockfalls. We present the 3D modeling results of the gravel motion along the slope ending with a horizontal accumulation area in this paper. We obtained the modeling results using the two-fluid model. The base of the two-fluid model is the continuum approach, and the flow motion is represented as the motion of two interacting continua (gas and solid particles). In this model, the continuity equation and the momentum equation are solved for the two phases (the gas phase and the solid phase). We used a free open source software OpenFOAM, in which the two-fluid model was implemented. We compared the obtained results of calculations with experimental data. The calculation results are in good agreement with the experiments. The results of 3D modeling describe the motion of the gravel mass along the slope and the horizontal accumulation area from the experiments qualitatively. There is a small quantitative difference between the results of calculations of the runout of the gravel mass after rockfalls and the experimental data. We concluded, that the two-fluid model can be used to simulate the falling rock.