Investigation on the Mechanism of Hammer Sinking of Extra-long Steel Pipe Piles for Cross-sea High-speed Railway Bridges
In view of the lack of field test of super-long steel pipe piles for cross-sea high-speed railway bridges and the problems of verifying the design parameters of pile foundations,relying on the Hang-zhou Bay Cross-Sea Bridge project,the initial and re-driving high strain test and static load test are carried out on super-long steel pipe piles,to analyze the sinking mechanism of steel pipe piles such as the bearing capacity performance,penetration characteristics and other sinking mechanism,to further verify the design parameters of the pile foundations,and to provide the basis for the large-scale pile sinking operation.The results of the study show that firstly,under the geological conditions of this test pile area,using YC80 hydraulic hammer and HHD1000 hydraulic hammer with normal working performance,the energy transfer efficiency is in the range of 63％to 84％,which meets the require-ments of the same type of engineering piles for pile sinking construction.Secondly,there is a bias of conservative phenomenon in the assessment of the bearing capacity of the large diameter monopile foundation by high strain testing method,which reduces the value of the bearing capacity by 18.35％comparing with that of the static test value.Thirdly,the coefficients of restoration of the axial com-pressive bearing capacity of test piles SZ-1 and SZ-2 are 1.37 and 1.56,and there is a significant time effect on the bearing capacity of steel pipe pile after sinking.Lastly,the measured soil plugging effect coefficients of test piles SZ-1 and SZ-2 are 0.71 and 0.3,and there is a significant soil plugging effect of the extra-long steel pipe piles.
万方数据
维普
