The calculation method of the limit bearing capacity of the non-uniform piles and the composite foundation is studied on the basis of the swelling failure theory,the earth pressure theory and the friction in the contact surface between pile and soil.

With the example of taped pile, the buckling problem of variable section piles was analyzed with the energy method.

Study on longitudinal vibration of pile with variable sections in the viscous damping soil and its applications;

The vibration problem of pile with variable sections and finite length under exciting force is studied.

To choose cross-section of pile reasonably in the theory and engineering appliance of composite foundation,finite element method was adopted to analyze respectively,in a 3-D elastic analysis,the deformation properties of circular cross-section pile and square cross-section pile in pile group of composite foundation under horizontal load,when different multi-layered soil conditions were considered.

To choose cross-section of pile reasonably in the theory and engineering appliance of composite foundation,finite element method was adopted to analyze respectively,in a 3-D elastic analysis,the deformation properties of circular cross-section pile and square cross-section pile in pile group of composite foundation under horizontal load,when different multi-layered soil conditions were considered.