In order to study the effect of the center-to-center spacing of piles and the width of pile caps on the soil arching in a piled embankment with reinforcements,field tests were performed at the Qing Feng toll station constructed on a geogrid-reinforced and PHC pile-supported embankment in the Guangzhou-Qingyuan highway extension project.The contact pressures acting on the pile caps and the surrounding soil were measured in the conditions of different widths of pile caps and spacings of piles,and the relation between the height of soil arch and the clear spacing of pile caps was obtained.The test results show that the vertical stress in the surrounding soil is distributed uniformly.The height of soil arch decreases with the increasing of the clear spacing of pile caps when the spacing is larger than 1.0 m.The pile cap-soil stress ratio increases with the increasing of the embankment load,while decreases with the increasing of the width of pile caps and the spacing of piles.The load sharing ratio carried by the pile caps increases with the increasing of the embankment load and the width of pile caps,while decreases with the increasing of the spacing of piles.The load sharing ratio carried by the surrounding soil decreases with the increasing of the embankment load and the width of pile caps,while increases with the increasing of the spacing of piles.