Prediction Of Scouring Depth And Safety Evaluation Of Wading Pile Foundation

In recent years,there have been a lot of bridge destruction accidents due to the current erosion.The scour phenomenon mainly occurs under water,which has a high degree of concealment to the destruction of the bridge,and seriously threatens the safety of the bridge structure and users.Therefore,it is of great significance to predict the erosion depth of bridge pile foundation and evaluate its safety performance.This paper mainly focuses on the Bridges in ganjiang river basin,jiangxi province,and studies the deficiencies in the calculation of pile foundation erosion depth and the safety performance evaluation after erosion.Research contents and results indicate:(1)analyzed the erosion mechanism,calculated the domestic erosion formula with engineering examples,and made a comparison with the actual riverbed cutting depth.The calculation results show that the calculation from the existing scouring formula cannot reflect the true exposed depth of pile foundation.(2)This paper investigates the hydrological data of hydrological stations in ganjiang river basin and analyzes the causes of riverbed cutting in ganjiang river basin.The existing calculation formula of scour is modified.(3)the finite element model of the lower part of Midas civil bridge was established,and the stress conditions of different scour depths were studied respectively to evaluate the impact of scour on the mechanical properties of pile foundation.The calculation results show that the erosion will cause the pile internal force to increase,but it is still within the safety value range,and does not pose a threat to the bridge safety;The displacement of the top of the pier increases greatly and exceeds the safety value,which will have a great impact on the superstructure.(4)The existing pile foundation strengthening technology is improved,and the method of section augmenting and glass fiber sleeve strengthening is numerically simulated to evaluate the reinforcement effect.The calculation results show that the method of cross section augmentation can restore the safe value of pier top displacement and achieve the reinforcement effect.The method of glass fiber sleeve reinforcement can improve the stress and durability,and has little effect on the restoration of stiffness.The above research can provide reference for the design and reinforcement of bridge pile foundation.