Dynamics Of Two-layers Granular Column During Quasi-static Collapse

The collapse and flow of granular materials have been the focus of an increasing amount of research in recent years,because the properties and behaviors of static piles are fundamental to natural catastrophic events such as landslides,avalanches,and civil engineering projects(such as retaining wall and dyke).Recent years,a certain of qualitative analyses which focus on the comparison between numerical simulation and morphology evolution during collapse were conducted,while a few quantitative experiment does.We designed and assembled a set of experimental apparatus,in which the collapse of two-layer granular column occurred.As the system is quasi static,the three-dimensional movement of the particle along the horizontal can be described by the two-dimensional particle motion on the side walls.After that,we compile an image acquisition process called Particle Tracking to obtain the location information of every particle at every moment.We draw the trajectory images of all particles,the contours of slippage and vector diagrams.We observe that the slippage(S)formed in a state of layer morphology,as change steadily with the increase of a parameters.The direction of particle agree with the direction of slip layer.The slip layer angle of big ball is about 54°while the small ball is 45°.Ultimately,we conduct a model and a self-compiled MATLAB calculation program which corresponding to the model called Moving Boundary Calculation to calculate the position of any particle at arbitrary space-time.After verification,the results are consistent with the image of the experiment.Finally,through the self-prepared particle layer boundary recognition program Boundary Identification to provide some new ideas in data collection simplicity and accuracy.The result of our experiment could reveal the mechanism of the system in which the particle collapse,and then the theory could provide an experimental reference to the quasi static collapse behavior.