The Impact and Dynamic Behavior of Falling Rock Clusters - Insights from Experimental and Numerical Investigations PDF Download

Author: Ge Gao
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Languages : en
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Book Description
"Rock clusters falling down an inclined slope is a problem of growing concern in mountainous regions and poses a significant risk to people, roads, and other infrastructure. Different aspects of the problem have been previously investigated using physical modelling and numerical analysis. However, three dimensional impact force distribution on a barrier wall resulting from rockfall over a rough slope is scarce in the literature. In this study, a series of experiments are conducted to track the movement of granular particles down a slope and measure the impact force imposed by the falling rock clusters on a nearby vertical wall. The rock blocks are released from a container located at the top of the slope and the velocity profiles are recorded using marked pebbles and a high-speed camera. The effect of the rockfall volume, slope angle, and distance to the wall on the velocity profiles and impact forces are investigated. Validated using the experimental results, discrete element simulations are performed using PFC3D to evaluate the effect of particle sizes on the flow characteristics and final impact pressure on the structure. Analysis showed that impact energy is highly affected by the slope inclination, the shape of rock clusters, and runout distance. The research results have been submitted in refereed journals and have been published in conference proceeding amounting to 2 journal papers and 1 conference paper. These papers are compiled to produce 5 chapters in this manuscript-based thesis. The investigation of the effects of sphericity and angularity of particles on the dynamics of rockfall is first conducted using three dimensional distinct element method (DEM) to illustrate the importance of the consideration of sphericity and particle shape in modelling rockfall problems involving movement pattern and impact forces on the rigid barrier structure imposed by the falling rock clusters. The rest of the thesis is devoted to comprehensively analyze the influence of the irregular-shaped particles on the dynamics behavior of rockfall and impact forces exerted on the rigid structure in discrete element method. Replication of the experimental system, the calibration procedure needed to determine the propertiesof the discrete elements is necessary for a reasonable numerical simulation (e.g. restitution coefficient, internal friction angle). By adopting a suitable damping ratio and friction coefficient among the contacts for each distinct element, the numerical accuracy of the falling rock clusters has been maintained. Conclusions and recommendations are made regarding the slope inclination, volume effect on the impact imposed by falling rock clusters on rigid structure." --