3D Numerical Analysis on Mechanical Deformation Characteristics of Geogrid-reinforced and Pile-supported Composite Foundation

The mechanism of geogrid-reinforced and pile-supported earth platform composite foundation is very complex. Based on the experience for the design and calculation,some blindness in the design and construction will be produced. Three-dimensional model for pile group is established by Finite Element analysis software Ansys,and mechanical deformation characteristics of geogrid-reinforced and pile-supported earth platform composite foundation are analyzed. Base on an engineering example,the results between numerical simulation and field monitoring are compared,and both are more consistent. The results are as followed: both pile and pile end soil have optimal modulus of elasticity; the maximum pile-soil stress ratio is present to a certain depth on the top of the pile,and the maximum pile axial stress is present to the neutral point on the top of the pile,the pile-soil stress ratio and the pile axial stress decrease suddenly due to the stress concentration is produced at pile end. The stiffness of pile end soil has some influence on pile-soil stress in a certain depth from the bottom of pile. The stiffness of geogrid reinforced cushion has some influence on soil stress between piles under a certain depth on the bottom of cushion. The regulatory role for pile-soil stress ratio is more significant when the low stiffness. The size of geogrid reinforced cushion has some significant influence on pile axial stress and pile side frication stress,the most significant influence is present to 0. 3 times pile length on the top of pile.