Abstract: Laboratory model pile cap tests are performed. The objective of these tests are to investigate the influence of different types of pile caps on the soil arching effect of rigid pile composite foundation, to fully utilize the mechanical properties of rigid pile composite foundation and to improve the bearing capacity and stability of composite foundation. These laboratory model tests are focused on the rigid pile composite foundation under different types of pile caps. The mechanism of soil between piles, pile head pressure, pile load sharing ratio and soil settlement between piles are investigated. The following results are obtained: (1) With the increase of embankment filling height, the soil pressure at the top of pile cap, between piles and the load sharing ratio of pile body increase, and the soil arch effect causes some embankment loads to transfer to pile shaft, and the soil arch effect gradually strengthens with the increase of the compression modulus of the bulk particle of pile cap. (2) under the same embankment height, the soil pressure at the top of the pile cap decreases with the increase of the top side length of the bulk solid, and the increase of the top side length of the bulk solid will inhibit the soil arch effect, while the change of the thickness of the pile cap has a small effect on the soil arch effect. (3) The application of the pile cap with the bulk solid in the rigid pile composite foundation has a certain effect on the soil arch effect.

Key words: Pile Cap Types, Pile Cap with Bulk Solid, Rigid Pile Composite Foundation Cap, Embankment Load, Soil Arching Effect