Abstract: The existing multivariate composite foundation uses two or more kinds of piles to strengthen the foundation soil in order to improve the bearing capacity and accelerate the consolidation of the foundation. In this paper, a consolidation model of permeable concrete pile composite foundation, which has the advantages of both bulk material pile and rigid undrained pile, is proposed. In the practical project, the compression amount of rigid pile and soil is not equal, which is inconsistent with the equal strain condition. For this reason, this work abandons the traditional equal strain hypothesis, considers the amount of penetration of the pile to the cushion and underlying layer, and modifies the traditional equal strain hypothesis. At the same time, the parabolic change of horizontal permeability coefficient of soil in disturbed area and the blocking effect of fine particles on water seepage in permeable concrete pile are considered. Besides, the governing equation and solution of this kind of consolidation problem and the expression of consolidation degree of composite foundation are given. The solution of consolidation degree of composite foundation is also discussed. Finally, the solution of this work is compared with other composite foundation solutions, the consolidation behavior is analyzed, and the influence of pile resistance caused by pores of permeable concrete pile on the consolidation velocity of foundation is verified.

Key words: consolidation, permeable concrete pile, composite foundation, modified equal strain, penetration deformation