| Pile foundation is the most widely used form of deep foundation in high-rise buildings.It is an important part of the building structure and plays a very important role in the quality and safety of the engineering structure.In actual engineering,in order to improve the vertical bearing capacity of the pile foundation and meet the settlement requirements,it is often required that the pile tip pass through the hard interlayer to reach the hard bearing layer,while the pile tip passes through the hard interlayer and requires greater pressure to avoid pile pressing.In order to avoid the damage of pile breaking caused by high pressure in the process of pile pressing,the enterprise developed the double static pressure prestressed concrete pipe pile.It used the method of top pressure and internal pressure rod to sink the pile,which is the internal pressure rod and the pile body were shared by the composite pile feeder.The technique of composite static pressure sinking pile realizes that the pile tip reaches the hard bearing layer by high pressure sinking pile,which increases the final pressure during pile pressing,and then increases the vertical compressive bearing capacity of high-strength prestressed concrete pipe pile.In order to study the pile sinking technology and bearing capacity of the dual static pressure prestressed concrete pipe pile,this article is familiar with the current situation of the research on the bearing performance of prestressed concrete pipe piles at home and abroad,and uses the double static pressure prestressed concrete pipe pile in the actual project.For the research object.The force analysis of the pile pressing process,the laboratory study of the pile pressure resistance and the force performance of the pile shoe plate,the field pile sinking and static load test study,and the use of ABAQUS finite element software to analyze the dual static pressure prestressed concrete pipe pile The pile sinking process,single pile bearing performance and pile shoe plate force performance are simulated and analyzed.The sinking technology of dual static pressure prestressed concrete pipe piles,the design and structure requirements of the pile shoe plate and the single pile bearing capacity are given.The main conclusions of this paper are as follows:(1)The use of dual static pressure pipe piles with internal pressure rod and pile body to bear the pile sinking pressure can reduce the pressure of the pile body during the pile sinking process,ensure the quality of the pile body,and make the pile tip reach the hard bearing layer;(2)The characteristic value of the vertical compressive bearing capacity can reach1800 ～ 2000 k N,which can meet the basic bearing capacity requirements of general high-rise buildings;(3)The pile shoe plate of the double static pressure prestressed concrete pipe pile studied in this paper is recommended to adopt Q235 grade,25 mm thick steel plate orQ355 grade,16 mm thick steel plate with the same diameter as the pile,which can guarantee the double static pressure prestressed concrete pipe pile Piling process.It is recommended that the pile boots be completed in the factory when the pipe piles are processed to avoid on-site welding affecting the construction quality;(4)The final pressure control is the main method for the dual static pressure prestressed concrete pipe pile driving process,and the elevation control is the supplementary method.The process is as follows: before the pile sinking pressure reaches 3000 k N,the conventional method of holding pile sinking is adopted;after that,the internal pressure rod is inserted into the hollow of the pipe pile,and the pile is sent to the end of the pile with a composite pile feeder under double static pressure.Reach4500 k N.In the process of double static pressure pile driving,the energy is transmitted to the pile shoe through the internal pressure rod and the pipe pile,and then to the soil at the end of the pile,which increases the pile driving pressure by 150%. |
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