This thesis presents a comprehensive investigation into excavation-induced swelling in soft clay soils, with a specific focus on the influence of embedded structural elements and pile installation effects. The motivation for this research stems from the conservative nature of
traditional analytical methods, which tend to overestimate swelling due to their simplifying assumptions—highlighting the need for a simple yet more advanced modeling approach that captures soil-structure interaction more realistically. The research integrates both analytical and numerical methods to assess vertical deformation and swelling pressure under varying geotechnical configurations. The analytical approach employs the Koppejan method, a classical consolidation-based method, to estimate heave resulting from dissipation of excess
pore water pressure during the last phase of consolidation. Implemented in Excel, the analytical model assumes idealized elastic soil behavior and uniform unloading. This method serves as a
baseline for identifying trends and quantifying the level of conservatism in traditional estimates.
The numerical simulations are carried out using PLAXIS 2D, applying the Hardening Soil model to realistically capture the nonlinear behavior of soft clay. Various scenarios are modelled, including the presence or absence of floor slabs, embedded piles, and volumetric
expansion resulting from pile installation. Volumetric expansion is introduced via prescribed initial strains, mimicking the stress redistribution caused by displacement-type pile installation.
Five structured cases are developed to isolate and analyse the effects of pile stiffness, spacing (centre-to-centre distances of 2 m and 2.5 m), floor rigidity, and interaction effects.
Results demonstrate that analytical methods consistently overestimate both swelling displacements and floor swelling pressures by up to 70% in some configurations due to their
inability to account for soil-structure interaction and stress redistribution. Numerical findings highlight that embedded piles, particularly when closely spaced and combined with stiff floor
systems, significantly reduce the magnitude of swelling and associated pressures. Additionally, pile installation effects play a vital role in stress buildup, altering pore pressure dissipation and
influencing upward soil movement.
This dual-framework approach offers critical insight into the mechanisms driving swelling in excavation contexts and provides practical guidance for improving predictive accuracy in
design. The outcomes underscore the necessity of incorporating installation effects and realistic structural modeling in modern geotechnical practice.