Calculation of Pile-soil Stress Ratio of Rigid Pile Composite Foundation with Consideration of Upward Penetration of Piles

Abstract

Deformation performance of rigid pile composite foundation under vertical loading was discussed, and the relationship between the pile lateral friction and the relative deformation of piles and soil was studied. By adopting the concept of the equal settlement section, piles and surrounding soil were assumed to be linear elastic masses, and the distributions of pile lateral frictions above and under the equal settlement section were assumed to be linear along the pile, respectively. On the basis of the deformation coordination of pile-soil-cushion and the load transfer method, a calculation formula of the pile-soil stress ratio was proposed. The positive and negative skin friction resistances along the pile, the upward and downward penetration of the pile, diameter and length of the pile and soil layer property were taken into account in the presented method. Finally, in order to verify the presented method, the pile-soil stress ratio of a group-pile composite foundation test was analyzed. The result shows that the calculated results are close to the test results when the pile lateral friction resistance exert sufficiently.