Application Research Of Double Static Pressure Pipe Pile

High-strength prestressed concrete pipe pile(referred to as PHC pipe pile)is a precast pile widely used in pile foundation engineering.PHC pipe piles have good quality and strong controllability of bearing capacity.Two hammer sinking and static pressure sinking methods are usually used.To achieve higher single pile bearing capacity and the need to cross deep and thick sand layers or other hard When sandwiching,it has high requirements for the pile sinking capacity of the pile driver machinery,and the bearing capacity of the pile body should also be matched with them.Both are indispensable.When PHC pipe piles are piled,it is often difficult to pass through the hard interlayer to reach the hard rock and soil layer due to the insufficient pile driving capacity of the pile driver machinery or the insufficient strength of the pile body,and only a lower bearing capacity can be used.In view of the limited bearing capacity of PHC pipe piles,the conventional static pressure method for pile sinking cannot achieve a higher final pressure value,the resistance of the pile end is difficult to exert,and the final pressure value in the hard interlayer such as sand layer is insufficient,resulting in vertical Weakness of low compressive bearing capacity,discuss the use of double static pressure pipe pile construction technology,that is,the top pressure + internal pressure bar to double static pressure sinking PHC pipe pile,so that the pile end reaches the hard bearing layer to increase pile end resistance,Significantly improve the vertical compressive bearing capacity of PHC pipe piles.To this end,the following work was carried out:analysis and elaboration of the stress mechanism and bearing capacity influencing factors of the double static pressure pipe piles;the test site of the typical stratum was selected,and the field test of two batches of 13 test piles was carried out to complete The pile body integrity detection,static load test and data results are sorted and analyzed,and the control method of the pile quality and bearing capacity during the construction process of the double static pressure pipe pile is obtained;the double static pressure pipe pile is adopted by the ABAQUS numerical simulation software The pile driving process,the vertical compressive bearing capacity of single pile and the vertical compressive bearing capacity of three pile foundations were numerically simulated,and compared with the test data to study and discuss the working characteristics of double static pressure pipe piles;The engineering trial design of the double static pressure pipe pile was compared with the conventional static pressure PHC pipe pile in terms of engineering technology,economic benefits,and bearing capacity.The conclusion of Ligao is that the pile is suitable for the geological conditions of Changchun area,and it is recommended to be promoted and used in other areas where the burial depth of the supporting layer does not exceed 15 m.