A study of the process of particle column collapsing into water under 2D condition

Impulsive wave and its secondary disasters, which are caused by the collapse of risky tower rocks, occur frequently in southwest China. Characteristics of the impulsive wave are closely related to the initial shape and failure mode of the disturbance source, the failure mode of collapse of risky tower rock mass from bottom to top and disintegrate in the air is similar to that of the collapse of granular column. Different from the rigid body materials and the motion distance to obtain the initial dynamic state used in the past wave test, this paper designs and carries out the physical model experiments of different heights and widths of particle column collapse at different water depths by using the PIV technology to analyze the movement characteristics of particle and water body.According to the interaction between particles and water, the whole process is roughly divided into three stages, and the influence of initial shape of particles on the test results is examined. The results show that the residual volume after the collapse of the granular column is greatly influenced by the initial shape of the granular body, while the water depth has little influence on it. There is a good corresponding relationship between the position of the first wave and the position of particle movement in the early stage of impulsive wave, and the distance between them began to increase. The higher the particle column is, the greater the difference between the position of the maximum wave height of the first wave and the position of the front end of the collapse particle group is, which may be caused by the fact that the velocity of the water body in the later stage of the fluid solid interaction is greater than that of the particle flow. Most of the generated waves have complete waveforms, which is related to the inhomogeneity of the effect on the water body caused by the covering accumulation characteristics of the columnar particle collapse and the dispersibility of columnar particles. The experimental results reveal the characteristics of the mechanism of the impulsive wave caused by the risky columnar rocks and may provide the basic data for the prevention and control of the surge disasters.