Critical transverse differential settlement between modern tram pile-plank-supported subgrade and surrounding pavement subgrade

Due to the great structural difference between the modern tram pile-plank-supported subgrade and the surrounding pavement subgrade, pavement disease induced by the uncoordinated transverse settlement between these infrastructures continue to appear. A centrifuge model test combined with a finite element method (FEM) was employed to investigate the development law of transverse differential settlement between these infrastructures subjected to long-term operation loads. According to the relationship between horizontal stress and differential settlement rate, the critical transverse differential settlement of tram pile-plank-supported subgrade was proposed. The results showed that the tram track layout, soil stress history and operation time had a great influence on the transverse differential settlement of the tram pile-plank-supported subgrade. During the operation time, the transverse differential settlement rate was linearly related to the horizontal stress of the tram pile-plank-supported subgrade. Finally, according to the requirements of allowable tensile stress of the pavement structure layer, definition of the value of 3.0‰ was suggested as the critical transverse differential settlement rate of the tram pile-plank-supported subgrade.