Evaluation of Static and Dynamic Behavior of Rigid Columns

Abstract

Construction on soft soils often requires utilization of ground improvement techniques in order to solve the problems associated with bearing capacity and stability. These techniques, in addition to traditional preloading techniques, include various applications to the ground based on rigid columns. Today, rigid columns can be modelled on a computer using the finite element method (FEM) prior to the implementation in the ground and complex ground-structure interaction mechanisms associated with the applicability of a suitable soil improvement technique can be investigated. In this study, rigid columns including rammed aggregate piers (RAP), jet grouting (JG) and bored pile (BP), are tested in realistic finite element models for both static and dynamic cases. Here, we consider 17 m uniformly distributed load foundation in FEM modelling. Long term consolidation analysis is performed in the numerical models to compute stress and deformation variations for static case. The performance of  rigid columns in the numeric model is also computed using real earthquake data. In the static analysis, the settlement values prior to the ground improvement, was around 52.55 cm. After installation, the settlement values has dropped dramatically. Following the RAP installation, the value has decreased to 26.04 cm. We have also observed a decrease in other two installations where the settlement values are 19.11 cm and 7.3 cm for the JG and the BP installations, respectively. Our dynamic analysis also shows an improvement in the settlement values regardless of any rigid inclusion ground improvement. It is worthy of note that these installations considerably enhance building performance in the FEM models

Keywords

• FEM,Ground improvement techniques,Static -dynamic analysis

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