Research on the influence of soft interlayer to composite foundation

The influence of soft interlayer to composite foundation is researched through FEM analysis in the paper. From the result of study, we can see that the soft interlayer is more thick, the stress in the pile of composite foundation is more strong; the soft interlayer can amplify the pile shaft friction resistance; the law of the soft interlayer influence the subsidiary stress in soil between piles is corresponding to the transmit law of the soft interlayer influence the pile shaft friction resistance; the distance between the soft interlayer and the foundation bottom in back-up coat influence the foundation subsidence poorly; the thickness of soft interlayer influence the transformation isoline of composite foundation poorly in depth, but influence obviously in width.