Analysis of Axially Loaded Short Rigid Composite Caisson Foundation Based on Continuum Approach

Abstract

The concept of an open pipe pile with a gravel plug is used to develop a new short rigid composite caisson foundation for floodplains and lowlands. It consists of a shallow pipe or caisson, sunk to the desired depth by conventional sinking techniques; the soil within the caisson shaft is removed; and granular material is filled in and compacted to enhance the stability and load-carrying capacity. The caisson shaft is considered to be rigid, undergoes rigid body translation, and hence is analyzed as an incompressible cylinder, whereas the core inside is treated as a compressible pile. The soil displacements are calculated at the midpoints of the outer surfaces of each element and at the centers of the bases of the caisson shaft and the granular core by numerically integrating Mindlin’s solution for a vertical point load inside a semiinfinite medium. A parametric study is carried out to bring out the effects of various parameters on the load sharing, the shear stress distribution, and the settlement of the proposed foundation.