Abstract:
In order to investigate the influences of embankment height on the dynamic response of pile-raft composite foundation, a large-scale model test on the cast-in-situ X-shaped concrete (referred to as XCC) pile-raft composite foundation is carried out in a model box of 5 m× 4 m×7 m. Four different embankment heights are modeled as the dead loads, and the cyclic wheel axle load is applied to the raft so as to obtain the dynamic response with the dead loads (i.e., embankment height). The results show that the velocity response decreases by 34% ~ 40% from the top of the raft to 0.36 m depth of foundation due to the existence of a gravel cushion. The vibration of the raft caused by the axle load decreases gradually with the increasing dead loads. The relationship between the velocity response of the raft
v' and the dead load
x is defined by the equation,
v' = 12.648-0.519
x+0.007
x2. Both the dynamic soil stress on the surface of the foundation
σsd and the dynamic stress at the top of the pile
σpd decrease linearly with the increasing dead loads
x. The former is defined by the equation
σsd= 7.629-0.085
x, whereas the latter is defined by
σpd= 284.978-3.660
x.