Discrete element modelling of soil-pile interaction with emphasis on soil characteristics and pile installation methodology

Abstract

Soil-pile interaction is a complex geotechnical problem that requires rigorous multi-scale analyses. However, it is challenging to understand the micro aspects of this problem with either experimental approaches or continuum-based numerical models. On the other hand, the discrete element method (DEM) provides a powerful medium for modelling soils as particulate materials and can be used to examine soil-pile interaction at multi-scale. Accordingly, this dissertation aims to investigate soil-pile interaction with DEM modelling. For this purpose, three different subjects are discussed in this dissertation. Initially, a parametrical study has been conducted to clarify the influence of soil properties on pile penetration resistance. Later on, this study tackles the problem of computational cost; it is well known that one limiting aspect of DEM is its high computational demand. Regardingly, this dissertation also aims to clarify the validity of three techniques that are utilized to reduce computational time. In this respect, the appropriate parameters for DEM models are validated using the experimental results of a previous study. Lastly, this dissertation focuses on soil-pile interaction considering the effects of pile installation. Both jacked and replacement piles are installed into each sample and the response of the granular assembly is assessed in detail. Eventually, the jacked and replacement piles are subjected to vertical loading tests to determine their bearing capacity. The results obtained during pile construction and loading stages suggest that installation technique, in addition to soil density state and particle shape, also has a considerable effect on soil-pile interaction.