Model Test And Numerical Analysis Of The Curved Bank Failure Of The Yangtze River In Anhui Province

In the past decades,the frequency of bank failure has been increasing,and which leads to huge economic losses and casualties.The mechanism of bank failure has always been the focus of scholars all over the world.This paper combines indoor model test and numerical simulation to research the characters and effective factor of the bank failure process of binary structure bend river bank in the Anhui section of the Yangtze River.Using indoor model test,this paper analyses the changing characteristics of soil pressure,pore water pressure,settlement of slope crest,moisture content of bank in the process of failure,and summarizes the morphology of the failed bank.Based on the BSTEM model,the stability analysis of the typical sections of the Heyue Island was carried out to simulate the process of bank failure.The slope safety factor calculated under the condition of returning water was compared with the calculation results of our group using the critical slip field method of the unsaturated-unstable slope,the influence of the change of submersible position and the erosion of slope footing on the bank stability is summarized,and the influencing factors of bank stability are further analyzed.The results show that: The earth pressure value will abruptly decline when the bank fail,and the pore water pressure will fluctuate.During the sudden drop of water level in front of the slope,the river bank failure due to changes in slope morphology,lateral hydrostatic pressure,incomplete dissipation of pore water pressure,and reduced slope soil strength that caused by the sand layer being washed away.The characteristics of bank failure are closely related to the composition and mechanical properties of the river bank soil.During the dry season and the water rising period,the river bank is basically stable.The bank stability during the flood season is relatively lower,and the bank stability during the water withdrawal period is the lowest.The scouring intensity increasing of the slope toe will exacerbate the undercutting of the sand,and which leads the stability of the bank to be reduced and the failure to be greater.Comparing with the case of ignoring the water table retardation,the width of bank failure and the number of failure calculated by the model,which takes the influence of water table lag into consideration,is larger.It shows that the lag of diving water table will adversely affect the stability of the riverbank.Based on the model tests and numerical simulations,this paper studies the typical bank failure in the Anhui section of the Yangtze River,and analyzes the internal stress changes and the overall characteristics.The results provide reference for the study on the bank failure mechanism in the Anhui section of the Yangtze River.