| Bank slope instability and landslide surges are common geological hazards caused by increased pore water pressure on the bank slope,reduced effective stress and reduced stability of the bank slope which are due to the strong rainfall in the reservoir area and water level rise and fall as a result of water storage and flooding.As one of the secondary disasters of landslide disaster,landslide surge wave has the characteristics of instantaneity and unpredictability.The surge generated by the entry of the landslide body of the large reservoir bank carries huge energy.Once it happens,it will not only cause huge losses to the economic benefits of the reservoir area,but also affect the structural safety,stability of shipping and related dam projects.In severe cases,it may even threaten the safety of people's livelihoods on both sides of the reservoir,and the consequential indirect losses are incalculable.Therefore,studying the problem of landslide surge,especially the generation and propagation law of surge,has important theoretical value and practical significance for landslide surge disaster prevention and mitigation and related engineering construction.The research of landslide surge disaster is a complex interdisciplinary problem.The factors that affect it are also very complex,including the physical characteristics and sliding mechanism of the landslide body,the topographic characteristics of the river and water,etc.The hazard of landslide surge is mainly manifested in the strong turbulence of the water body caused by the landslide sliding into the water,and the surge wave height is an important indicator to evaluate the hazard.This paper uses the literature survey method and numerical simulation to carry out landslide surge-related research.This paper studys propagation characteristics and wave properties of landslide surges that do not consider the characteristics of the river channel,and explore the propagation wave height change law of the landslide surge under the influence of the channel characteristics.Based on the previous research experience and results,The river bend angle,water depth and water surface width of the river course are selected as the main influencing parameters The results and conclusions of the study are as follows.(1)By calculating the water movement mode and wave height duration curve of surge wave propagation in the process of landslide entering water without considering the influence of river channel characteristics,the generation and propagation characteristics of landslide surge wave are investigated.The nonlinear strength formula and Ursell parameter are used to judge that the landslide surge wave belongs to the weak nonlinear wave and the initial surge wave belongs to the isolated wave.Through in-depth analysis and discussion of the classical formula,it is found that the classical Noda formula and Pan Jiazheng formula cannot calculate the influence of the slip surface Angle on the surge height,and the modified Ren Xing Wei formula and foreign empirical formula do not consider the complex river characteristics,so the solution of the formula needs further study.(2)The wave height variation law of wave propagation under the influence of different river characteristics is analyzed,and compared with the wave propagation law without considering the influence of river characteristics,the research results show that the bending Angle of river channel plays a positive role in the attenuation of wave energy.There is a negative correlation between river depth and surge height.The influence of river width on surge wave propagation is mainly reflected in the process of wave propagation.The larger the width of river channel,the smaller the peak value of wave height,and the occurrence time of wave peak is slightly earlier.With the increase of propagation distance,the maximum wave height of surge wave gradually occurs on the secondary wave,and with the decrease of width,the secondary wave peak value has a tendency to increase.Wave height attenuated to different degrees under the action of different river bending angles and water depth,which indicated that the two influencing factors acted on landslide surge wave propagation together.Based on the numerical simulation results and previous research results,the regressive analysis of the height of the surge wave is carried out,and the fitting formula considering the bending Angle of the river channel is obtained.(3)Surge was calculated under different channel characteristics influence on the vertical dynamic water pressure on the surface of the dam distribution,the results show that the distribution of the hydrodynamic pressure of dam and dam site,a landslide occurred in the distance,the distance is relatively close,powerful dynamic water pressure on the upper and lower due to the intensity of the landslide to the water at the bottom of the extrusion,the bottom of the dam surface dynamic water pressure is very big,when the surge to a certain distance,upper powerful dynamic water pressure on the lower,and gradually decrease with the increase of the propagation distance and the water level and vertical distribution. |
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