As one of the most important factors

pile-soil stress ratio can reflect the load transfer and deformation mechanism of composite foundation. Up to now

as a new pile

no uniform method has been found to calculate the pile-soil stress ratio for X-section pile. Sedimentation basin and filter chamber are typical buildings with concrete floor plate that is considered to be a rigid base. The bearing capacity of pile composite foundation under the rigid base is different from which under the soft base. The in-situ static load tests are carried out based on the foundation treatment project in Qiaobei sewage treatment plant. Besides

a finite element model is built to simulate the cast-in-place X-section concrete pile composite foundation under the rigid base by software ABAQUS. The pile-soil stress ratios are discussed considering some factors including elastic modulus of pile

compression modulus of surrounding soil

pile lengths

cushion thicknesses and compression modulus. The results reveal that the pile-soil stress ratio increases with the increasing of pile modulus

cushion modulus and pile length

while reduces with the increasing of modulus of surrounding soil and cushion thickness. The reasonable pile-soil stress ratio of X-section pile ranges from 20 to 25

corresponding to the pile modulus from 10 to 20 GPa

the cushion thickness from 20 to 40 cm

and the cushion modulus from 30 to 45 MPa.