Stability Analysis Of Arch Bank Slope Of Luowang River Bridge Based On Fluid-solid Coupling

Instability of bank slope is common in triver basin.This phenomenon is particularly evident in the reservoir area due to frequent fluctuations in the water level.The instability of the bank slope will not only lead to the destruction of the buildings along the coast and cause the loss of life and property,but also destroy the land resources on both sides of the river and affect the navigation conditions.For long-span arch bridges built in the reservoir area,the arch seats often need to be set on the steep reservoir bank slope.The bank slope is under the condition of the river water level rise and fall for a long time,facing the potential risk of instability.Therefore,it is of great significance to carry out research on the impact of reservoir water level changes on the stability of arch bank slopes.This article takes the Guizhou Luowang River super large bridge as the engineering background,and carries out numerical simulation analysis based on the special geological survey and related theory,and conducts the stability study based on fluid-structure coupling for the bank slope before and after the bridge construction.The main work of the paper is as follows:(1)Summarize the finite element coupling theory of porous media seepage fieldstress field,summarize the commonly used slope stability analysis methods,and compare the calculation results of the limit equilibrium method in the classic example with the calculation results of the finite element strength reduction method of ABAQUS in the paper.Verify the accuracy of the ABAQUS calculation method;(2)Use the finite element software MIDAS/Civil and ABAQUS to establish reasonable full bridge model and three-dimensional arch-bank slope model respectively.Two-step finite element analysis method and finite element strength reduction method were used to analyze the influence of water level factors on the bank slope stability of Luowang River Bridge,including steady-state water level height and transient rise and precipitation rates.Calculate the distribution of seepage field,displacement field,stress field,plastic zone and velocity field under different seepage conditions of the arch bank slope,and analyze the variation law of each field variable;(3)From the perspective of bridge design,consider the effect of additional displacement of arch foot caused by water level changes on the internal force of the main arch ring,and give suggestions on the value of additional displacement of arch foot in the design,for the future design of arch bridge under such geological conditions for reference.At the same time,the multiple linear regression is used to establish the relationship between the bank slope safety factor and the water level change rate and bank slope slope,and fitted into an empirical formula;(4)Study the influence of water level factors on the natural bank slope without arch.In the finite element model,the arch and its associated boundary conditions were removed,and the effects of steady-state water level height,transient rise and precipitation rates on the stability,internal force,and deformation of the natural bank slope were studied,and the shore was compared with and without bridge load.The mechanical law of the slope presents,analyzes and summarizes the influence of the bridge load on the stability of the bank slope.