To analyze the settlement and deformation characteristics and the failure modes of embankments on soft ground reinforced by plain concrete piles

three centrifugal test models of the embankments on soft ground reinforced by plain concrete piles with different spaces between piles and their numerical models have been performed. The results show that changing pile spacing has a remarkable effect on the settlement and deformation

the pile shaft strain

the failure modes of piles and reinforced cushion of the models

under embankment self-weight load

and track structure and vehicle load. When the pile spacing is not greater than 4 times of the pile diameter

the reinforced cushion can basically maintain integrity

the settlement of the models gradually tends to stabilize. Once the pile spacing increases to 6 times of the pile diameter

the reinforced cushion is impaled

the function of deformation coordination and load transfer would not be available

resulting in a continual increase of the settlement of the model embankments. While the pile spacing reaches 4 times of the pile diameter

an abrupt decrease in the maximal strain value of the piles occurs with increasing upper load

and the plain concrete piles near the embankment toe fail firstly in bending failure mode rather than shear failure mode. The plain concrete piles closer to the embankment center fail gradually in bending failure mode as the pile spacing increases to 6 times of the pile diameter.