Abstract: This paper has deduced the effected diameter of a closed large diameter pipe pile on sand ground as well as the horizontal resistance (or moment) acting on the rigid large diameter pipe pile. And, it provides the theoretically optimal design for the similar case; and by using the MATLAB program to analyze the axial stiffness of single pile, the relationships of stiffness of single pile, and the equivalent stiffness modulus of the soil beside the pile for unit depth, the equivalent stiffness modulus of the soil at the bottom of the pile, the thickness of the steel pipe pile, as well as its diameter, length and the elastic modulus for the used material are now much more clear. Based on this idea, the corresponding axial force can be calculated by using the load transfer hyperbolic function for known or assumed compressive deformation of the pile body.

Key words: large diameter steel pipe pile, settlement, carrying capacity, deflection, axial stiffness of single pile