Simulation Of Loess Bank Slope Collapse Disaster Process Induced By Scour Or Rainfall

Reservoir is an important water conservancy about people’s livelihood. Bankcollapse is a common bank slope disaster, and it is frequent and serious. Lots ofresearches on the issue of bank collapse disaster were studied, but the research workwas mainly concentrated in disaster qualitative prediction and the carried quantitativework had some limitations, such as, either research on bank slope collapse byscouring single with river dynamics theory, or prediction and evaluation on slopestability analysis single with rock and soil mechanics. In addition, loess bank collapsemechanism and disaster process became more complex for special mineralcomposition and morphology of loess. With Xiduancun Reservoir, combinedinterdisciplinary theories and methods with engineering geology, unsaturated soilmechanics, river dynamics and fluid mechanics, loess bank slope deformation law byriver scouring, water level fluctuation and rainfall infiltration was sdudied. The maincontent includes:(1) Many data about bank slope collapse collected, unsaturated nature of loesssummarized, study of loess bank slope collapse discussed, the influence of scouringand rainfall on the slope stability was summarized.(2) The hydrodynamic conditions of reservoir studied, features of the ancientslope and geological environment conditions for study area were surveyed. On thisbasis, a typical geomechnical model for loess bank slope collapse was set up.(3) Based on the principle of bank slope scouring, the typical profile of bankslope selected, horizontal broadening distance and vertical cut distance with a certainperiod of time calculated, from this, the impact of scouring on the slope was obtained.(4) Water level fluctuation is the normal process for reservoir. Through numericalsimulation, the influence of water level fluctuation, different rate of decline and waterlevel fluctuations repeatedly up and down on the slope stability was got.(5) Through numerical simulation of bank slope under rainfall, the same rainfallintensity and different duration, the same duration and different intensity, the samerainfall quantity with different intensity and different duration on the slope stability was achieved. The time of bank slope instability with different rainfall intensity wasrequired.(6) The variation of slope stability coefficient with water level and rainfalltogether was got.