Study On The Impact Force Model Of Granular Flow Based On The Model Experiment

Granular flow is generally caused by landslides or mountain collapses.Frequent earthquakes accelerate the formation of granular flow impact disasters,and its huge impact force will cause serious damage to the protective structure along the way.Carry out the impact model research of granular flow on the protective structure,which not only helps to improve the understanding of the mechanism of the granular flow impact,but also contributes to the design of the protective structure of the granular flow impact disaster and the intensity of the granular flow.Based on the on-site investigation of granular flow disasters and the review of relevant literature,this paper is supplemented by the means of indoor model experiment.From the point of view of the flow,impact and accumulation characteristics of the granular flow,the impact mechanics model of the granular flow impacting the rigid retaining wall is established,and the impact mechanism of the granular flow and the dynamic response characteristics of the protective structure are discussed.Based on granular flow data analysis and field investigation,the control factors affecting the impact force of granular flow are mainly granular parameters,slope parameters and protective structure parameters.Based on the model test of indoor granular flow impacting rigid retaining wall,it is shown that the inclination of the chute,the impact velocity and the flow thickness of the granular flow have a significant impact on the impact force and its distribution range.Based on the model experiment,the instantaneous mechanical model and continuous mechanical model of granular flow impact are established respectively,and the relevant formulas of the impact force and the height of the granular flow are derived.The application of the mechanical model is verified by comparison with the model test results.And further analyzed the impact of the base friction angle of the chute,the friction angle of the retaining wall and the impact velocity of the granular flow on the impact force.The results of the instantaneous mechanical model show that the maximum normal force and its action height are in good agreement with the experimental results,while the tangential force is less than ±20%.The results of the continuous mechanical model show that the analytical solution of the impact force and its action height is consistent with the experimental results.When the position of the reaction force of the substrate accounts for 2/3of the length of the accumulation zone,the effect height of the impact force is greater than the test value,which is theoretically safe.The maximum normal force and tangential force increase with the increase of the base friction angle.The friction angle of the retaining wall has a significant influence on the tangential force,and the impact velocity makes the normal force phase and the experimental value error ±15%.It shows that the theoretical model is acceptable,and the research results can provide reference for the disaster prevention and mitigation project of landslide or collapse granular flow.