Study On Defect Detection And Reinforcement Application Of Prestressed Concrete Pipe Pile

Prestressed concrete pipe pile is widely used in building foundation,retaining structure and foundation pit supporting structure because of its high carrying capacity,low cost,standardized production,convenient construction and convenient quality detection,especially in coastal soft soil foundation.The basic engineering is a concealed project,and the quality of the pipe pile directly affects the quality and safety of the construction.Therefore,the quality inspection of the project is very important.In this paper,the following aspects are studied for the pipe pile with quality defects in the process of engineering inspection:1.The main cause of the accident is analyzed by the engineering case of two large area excavation of pipe pile in Tianjin area.According to the test results of pipe pile integrity,the compression,and horizontal bearing capacity test and high and low strain dynamic testing test of field core filling and complete pipe pile are carried out.After comparing the changes of compressive bearing capacity,horizontal bearing capacity and integrity of pipe piles after filling,the conclusion is drawn that tubular piles can be reused after core grouting.2.The types and causes of pipe pile defects are explained from three stages,such as early production and storage,construction and pile sinking in the middle period,and the foundation excavation in the later stage.The prevention measures for reducing the risk of pipe pile defects are put forward,and the methods of strengthening and strengthening the defects which are easy to be adopted in Tianjin are summarized.In order to facilitate the flexible handling of pipe pile engineering accidents,a more reasonable remedial plan is made.3.For the pipe pile bearing vertical or horizontal force,the length of the core and the amount of reinforcement should be calculated by the formula for the reinforcement of the core of the PHC pipe pile in Tianjin.Through the finite element simulation,the stress situation of the composite pile structure after the filling of the defective pipe pile under the action of vertical and horizontal loads is analyzed.The verification results show that under the condition of satisfying cracking load,the strength grade of core filled concrete has little effect on horizontal bearing capacity of pipe pile,and the core length of core grouting is less than 1.5m,and the core concrete with C25 grade or above can meet the actual requirement.