Study On The Sunk Well Of Reinforced Concrete Technique In Treating The Pile Disease Of Bridge Caused By The Down-Cutting Of Riverbed

Down-cutting of riverbed means that the existing riverbed level is lower than before.Down-cutting of riverbed could lead to the decrease of the bearing capacity of pile and the instability of the bridge,even cause the destruction of the bridge.The static and dynamic characteristics of the bridge affected by the down-cutting of riverbed and the application of sunk well of reinforced concrete technology in treating the bridge disease were analyzed in this paper,choosing a bridge in Huanggang city as the engineering background.The results are as following:(1)The causes of riverbed based on the related research were summarized and the disease mechanism of the bridge caused by the downcutting of riverbed and the reinforcement design were studied in this paper.The research showed than two aspects must be considered when reinforcing the pile.First,the pile must be protected from the scour of the river.Second,the design must enhance the bearing capacity of the pile.The sunk well technology was the best scheme which can meet the all the requirements at the same time.(2)A common reinforcement method using sunk well and a method combined sunk well and supplementary piles were put forward in the paper,according to different amount of riverbed cut.The sunk well could protect the pile from erosion by river water and improve bearing capacity of pile foundation effectively.(3)A method for evaluating the bearing capacity of a bridge considering down-cutting of riverbed was put forward in this paper.The bearing capacity of bridge influenced by the riverbed cut was analyzed and the effect of sunk well reinforcement was evaluated according to an engineering example.The result showed that the stability,bending capacity and stiffness of the pile were mainly affected by the down-cutting of riverbed.And eigenvalue and dynamic characteristics were also affected,which lead to the increasing of the structural dynamic response under vibration load.And the bending capacity was greatly improved and dynamic characteristics were restored after reinforced by the sunk well.The disease of the pile caused by the down-cutting of riverbed was effective ely eliminated.