Study On Disease Detection? Assessment And Treatment Countermeasures Of Underwater Pile-column Joints In Service Bridges

The existing bridge has a considerable part of the lower structure in the water environment,the underwater environment is complex and variable,and the dry and wet cycle and other factors also lead to a more harsh environment for the bridge.In the case of water environment,the bridge is affected by various physical and chemical factors,and the congenital deficiency existing during construction is likely to cause the underwater structure to be more prone to various diseases than the water structure.In response to this situation,the main work and conclusions of this paper are as follows:1.The common substructure forms and common defects are summarized.The common types of diseases such as pile-column structure erosion cavities,exposed ribs and concrete spalling are introduced,and the causes of diseases may be analyzed in terms of construction and environment.2.The principle of underwater detection of sonar and the imaging effect of underwater work are analyzed.The workflow and precautions of underwater artificial photography and artificial exploration are expounded,and the effect of underwater photography is demonstrated.The advantages and disadvantages of the two methods are analyzed and compared.It is finally determined that underwater photography and artificial exploration are still the most convenient and practical detection methods.Combined with the shortcomings of underwater photography and artificial exploration technology,three methods for improving underwater photography effects such as clear water replacement,casing drainage camera and compartment camera are proposed.3.Four types of damages are assumed for the pile foundation of the pile foundation,the pile foundation is deviated,the pile foundation is deviated,the pile foundation is tilted and the pile foundation is damaged.The parameters are assumed for these diseases.Finally,the finite element software ABAQUS is used to damage the pile foundation.The force form and carrying capacity were analyzed.The influence of different parameters on the bearing capacity of the pile foundation was determined.The formula for calculating the bearing capacity of pile foundation under single disease and combined disease is given in the specific disease parameters.4.The existing norms are analyzed and evaluated for the underwater part of the substructure,and the shortcomings are analyzed.Combined with the residual bearing capacity calculated by different piles under different diseases,the methods and standards for grading evaluation of diseases under different characteristics are given,and the existing specifications are supplemented and improved.5.The overall model of the substructure was established.The influence of pile foundation defects on the stress and overall bearing capacity of the substructure was studied by the form of the middle part of the pile foundation.Finally,a method for selecting the repair reinforcement method for the given structure when the remaining ratio of the bearing capacity is determined is given.6.The underwater structure repair and reinforcement methods commonly used for underwater pile-column structures are analyzed.The effects of “jacket method” and enlarged section method on the maintenance of underwater pile foundation are analyzed and compared.Finally,the specific operation modes and operation points of the two reinforcement methods are verified by combining two engineering examples.