Development And Application Of Runout Model For Loess Flowslides

Landslides are a common geological disaster in China,especially in the Loess Plateau.Due to the special properties of loess,loess with high water content is prone to liquefaction,resulting in the occurrence of loess flowslides.Loess flowslides often show the characteristics of long distance,fast movement,wide disaster range and strong destructiveness,which poses a great threat to the safety of life and property of people in disaster areas.Therefore,it is necessary to predict the moving distance of loess flowslides to reduce disaster losses.With the popularization and application of computer technology,a large number of numerical models have emerged in the field of landslide motion prediction.However,there is still a lack of complete numerical models for loess flowslides.On the basis of previous researches,this paper firstly deduces the mass and momentum equations of two-dimensional continuous fluids,and simplifies them by depth integration,and then establishes the governing equations of the landslide motion model based on the slice method,in which the grooves are comprehensively considered.Finally,a simulation program is developed based on the governing equations of the model,and the program iteration process,program algorithm and software interface are given.The landslide runout model is verified from multiple angles based on the material state of the simulated object.Firstly,the simulation of pure fluid by the model is verified by the one-dimensional dam break analytical solution.Secondly,the simulation of solid particle flow by the model is verified by the aluminum rod experiment.Finally,the model is used to simulate the water tank experiment.The verification results show that the model has certain reliability for the simulation of different state objects and meets the basic calculation requirements.The landslide runout model is used to simulate and analyze typical loess flowslides,including Dagou landslide in Tianshui City,Yongguang #1 landslide in Minxian County and Heifangtai Dangchuan #2 landslide in Yongjing County.The results show that the pore water pressure model can well reproduce the fluidity of the landslide,but the degree of its influence on the landslide movement is closely related to the pore water pressure ratio;the entrainment model can simulate the volume change of the landslide due to entrainment;the channel shape model determines,to a certain extent,the accumulation pattern and local velocity variation of the landslide simulation.In this paper,the research on the runout model of loess flowslides aims to provide help for understanding the mechanism of such landslides,and to simulate the movement distance of potential landslides,so as to provide a certain reference for disaster prevention and mitigation.