Vertical interaction of grouped 3x3 piles

This paper presents the calculation method of the vertical interaction of grouped piles for very a rigid cap and a very flexible cap (raft/beam). The expressions for the calculation of axial stiffness of piles along depth for 4 soil models are listed: constant, linear, parabolic variation of soil modulus for the floating pile and two-layered model for the end bearing pile. A program for the analysis of the interaction in the form of a flowchart has been made and presented. Results of numerical analyses of redistribution between the piles in the group, of 3x3, due to the vertical interaction for the soil of constant stiffness by depth with two modules of elasticity of soil of 25 MPa and 50 MPa have been presented. For linear and parabolic distribution soil modulus by depth, the impact of varying the mutual distance of the piles 3D, 3.5D, 4D, 5D and 10D, for a RC pile length (7 to 12m) and having diameter of 60 cm has been studied. Forces and settlements for the zero and final iteration are presented in tables, as well as the bending moment for the zero iteration, determined using a difference method. Some possible development directions of such models have been indicated.