Physical Test And Numerical Simulation Of Reservoir Bank Landslide Surg

There are many landslide disasters in the reservoir area,and the distribution range is wide.The surge disaster caused by landslide has become a problem that cannot be ignored.Therefore,it is very important to study the characteristics of landslide surge generation and propagation in the reservoir area for the prevention of landslide surge disasters.This paper analyzes the influencing factors of landslide surge by analyzing the characteristics of typical landslide surge cases.According to the influencing factors,the physical model test of landslide surge is designed to study the characteristics of the formation and propagation process of landslide surge,and the empirical formula obtained from the test is verified with the numerical simulation results of landslide surge in engineering cases.The following conclusions are drawn :(1)Through the statistical analysis of the characteristics of typical landslide surge cases,it is concluded that the influencing factors of landslide surge are the water-entry volume of sliding body,the dip angle of sliding surface,the geometric characteristics of sliding body(length,width and height),the water-entry speed of sliding body and the depth of water body.The range of water entry velocity of the sliding body is 2.5 ～ 62.5m / s,and the range of landslide surge height is 6 ～ 91.8m.(2)According to the one-dimensional characteristics of flume test,considering the three-dimensional characteristics of actual landslide surge,25 groups of field model tests were carried out,including 16 groups of block landslide surge and 9groups of granular landslide surge.The test results show that the wave generated by the block landslide surge test belongs to the category of shallow water surface wave and deep water wave.The wave produced by the bulk test belongs to the category of deep water wave.(3)Based on the surge test data and multivariate nonlinear regression analysis method,in the surge generation stage,the empirical formulas of the initial surge amplitude of the block and bulk landslide surge in the three directions of the sliding body movement direction,upstream and downstream are established respectively.According to the power exponent of each item in the empirical formula of the initial surge amplitude of the block and the granular body in the direction of the sliding body movement,it is concluded that in the direction of the sliding body movement,the influence factors of the initial surge amplitude of the block landslide are the relative thickness of the sliding body,the Froude number of the sliding body,and the relative width of the sliding body.The influencing factors of the initial surge amplitude of the granular landslide are in the order of Froude number and the relative volume of the landslide.In the surge propagation stage,the empirical formula of the initial surge amplitude propagation attenuation of the landslide in the three directions of the sliding body movement direction,upstream and downstream is established.The formula proposed by predecessors is fitted with the surge test data,and the initial wave amplitude propagation of the surge in this study conforms to the power function attenuation law.(4)Engineering case verification.The No.V accumulation body at 600 m in front of the dam on the right bank of the dam site of the Suofengying power station is selected as the engineering case.The numerical simulation method is used to simulate the movement process and surge of the No.V accumulation body after instability.The simulation results show that the water entry form of the upper part of the deposit under the 100-year rainstorm condition is consistent with the water entry form of the granular surge test,and the upper part of the No.V deposit falls into the water velocity range of 10.2～13 m /s.FLOW-3D simulation shows that the surge height of No.V accumulation landslide is 11.8 m.According to the empirical formula of granular surge in this paper,the surge height is 10.3 m.According to Reference [ 55 ],the surge height is 13.2 m.The numerical simulation surge height is basically consistent with the calculated values of the two empirical formulas.