Abstract:
Typical evaluation indices of fouled ballast are discussed and a new one,
PFI, is proposed. A DEM simulation of direct shear box based on delicate ballast model is performed to study the shear performance of fouled ballast at various levels and to evaluate the rationality of the
PFI index. The results indicate that the shear stress of ballast decreases observably due to fouling, which depends on the fouling degree. In addition, the particle size of fouling also influences the shear performance of ballast. The shear performance of ballast drops as the fouling particle size decreases for the same material. Compared with
VCI,
PFI can take the effects of fouling particle size into account. Therefore, PFI can evaluate the fouling level of ballast more accurately.