DERIVATION OF ADAPTED SOIL SPRINGS FOR THE BUCKLING ANALYSIS OF SUCTION CAISSONS DURING INSTALLATION

The buckling capacity of suction caissons during installation must be investigated, as these are sensitive to buckling due to their thin-walled structure. A geometric material nonlinear analysis with imperfections, in which the soil is modeled using continuum elements, provides the most realistic results. Nonetheless, the modeling of the nonlinear material behavior of the soil as well as the consideration of multiple imperfection shapes are associated with a high modeling and computational effort. To avoid this, springs are often used to model the soil. However, the common approaches for determining lateral soil springs were developed experimentally for flexible piles and not short caissons. In this work finite element models are created to derive adapted soil springs for large scale tests on suction caissons. The comparison of the implemented soil springs with the soil springs from the guidelines shows that an adjustment of the commonly used springs is necessary. A factor that allows the springs to approximate the behavior of the continuum elements is formulated. Additional models that analyze the supporting effect of the soil on the buckling capacity of the suction caisson using continuum finite elements and soil springs foundations are developed. These models also compare the effect of the embedment depth and the soil bearing capacity.