Research On Sliding Impact Characteristics Of Tailings Debris Flow

Large dam instability and potential failure problems not only seriously threat the safety of people's life and property,but also seriously damage the environment.Tailings dam is a dam with very typical particle characteristic,and it is easier to lead to stability failure and dam break in flood season when compared with common reservoir structures.First of all,the paper based on the macroscopic movement and micromechanics theory to describe the processes of tailings dam break and analyze the tailings debris flow rheology mechanism.Meanwhile,taking one tailing dam accident as engineering background,and regarding this tailings dam failure which caused by heavy rain as the large deformation destruction of fluid,a series of lab model tests on the characteristics and influence factors for the movement of tailings debris flow was carried on.In addition,a three-dimensional break tailings sediment flow impact on a rigid structure simulation test based on the Smoothed Particle Hydrodynamics(SPH)module which embedded in LS-DYNA was completed.Finally,the consequence evaluation model of the tailings dam failure was established.Then it was used to finish consequence assessment of the background tailing dam accident.Main works and the results are as follows:1)During the indoor similar physical model experiments on tailings flow due to dam break,the waveform movement rule and intermittent tailings debris flows characteristic were obviously presented.The stress curve was very close to the zigzag waveform movement curve as time passing by.Besides,the second impact loads of the group coarse particle tailings were easier to occur and more tailings stockpiled in the tailings reservoir discharged together with floods when compared with group fine particle tailings.Considering macro damages and economic costs,the channel bed slope is more gentle,the tailings flow slide impact damage is smaller and storage capacity of the tailings in same height of tailings dam is greater.Meanwhile,the gully bed friction coefficient is smaller,the submerged slurry height of structures is higher and the intermittent debris flows characteristic become more obviously.In addition,with the height of check dam increasing,the slurry height and the impact force peak present linearly decreases,while storage rate of the tailings blocked after the dam present an opposite phenomenon.2)Based on the meshless particle calculation theory and results of model tests,the characteristics of tailings debris flow were researched and analyzed by SPH computing program.Comparison between calculated results and experimental data shows that thenumerical simulation is effective.In addition,discussion on influence factors of calculated deformation is selected to optimize SPH simulation model.According to different conditions,numerical simulation was done separately and the results displayed that viscosity coefficient of SPH particles can determine the simulation precision effectively.3)With the help of the assessment model of tailings dam failure impact and the available data,a severity evaluation of the accident of tailings dam failure was completed.Meanwhile,based on the flow characteristics and mechanical properties of debris flow,a series of disaster prevention and mitigation measures of tailings dam break accident were proposed.