Search

The pre-bored grouted planted (PGP) pile shaft consists of a core PHC pile and the surrounding cemented soil column. The shaft capacity of PGP pile is controlled by the PHC pile–cemented soil–soil interface. In this paper, the effect of curing time on the frictional capacity of smooth concrete pipe pile–cemented soil interface was investigated through pile–soil interface shear tests. The test results show that the peak skin friction of pipe pile–cemented soil interface increased with the curing time. Nevertheless, the normalized peak skin friction (peak skin friction/cemented soil strength) of interface decreased with the curing time. The thickness of the cemented soil layer had a large effect on the residual skin friction of pipe pile–cemented soil interface. The scale effect also existed in the smooth concrete pipe pile–cemented soil interface shear tests, as the stiffness and shear strength of interface would decrease with the pipe pile diameter, which would eventually induce the decrease of radial confining pressure of the interface. [ABSTRACT FROM AUTHOR]

The rigid pile composite foundation is widely used in highway projects in soft soil area as it can effectively increase the bearing capacity and stability of the foundation. While the research on the behavior and failure mode of rigid pile composite foundation under embankment is not enough, instability failure of rigid pile composite foundation often occurs in practical projects. This paper presents a centrifuge model test to investigate the load transfer mechanism, settlement characteristic and failure mode of rigid pile composite foundation under embankment. The test results show that: the soil displacement of different region in rigid pile composite foundation was different, obvious vertical displacement occurred in the soil under the center of embankment and the horizontal displacement was very small in this region; both vertical and horizontal displacement occurred in the soil under the shoulder of embankment; and obvious horizontal displacement occurred in the soil under the slope toe of embankment; moreover, ground heave also occurred near the slope toe of embankment. The soil displacement in rigid pile composite foundation had a large influence on the stress characteristic and failure mode of rigid piles, the compressive failure and bending failure would probably occur for the piles under the center and shoulder of the embankment, respectively, and the tension-bending failure would probably occur for the piles under the slope toe of embankment. The different failure modes of piles at different regions should be considered in the design of rigid pile composite foundation under embankment. The test results can be used to improve the design method for rigid pile composite foundation under embankment in practical projects. [ABSTRACT FROM AUTHOR]