Modelling Ground Vibrations Induced by Pile Removal

Abstract

Ground-borne vibrations from construction activities can propagate through layered soil and affect nearby vibration-sensitive buildings. This thesis develops and evaluates a numerical source-soil-receiver modelling framework for pile-removal-induced vibrations at TU Delft Campus Zuid, combining field measurements, CPT-based soil characterisation, frequency-domain finite element modelling and simplified soil-structure interaction (SSI) formulations.

Measured vibration data showed a non-stationary response, with the dominant frequency during pile removal developing from approximately 6-7~Hz towards a sustained component around 14~Hz. Because the mechanical source force was unknown, model-dependent equivalent vertical and radial forces were identified from near-source measurements and used as input to a two-dimensional axisymmetric free-field model. The soil profile was derived from 24 CPT soundings, with dynamic properties estimated using empirical correlations. Comparison with far-field measurements showed that the calibrated model reproduced the dominant frequencies more consistently than the absolute vibration amplitudes.

The calibrated free-field model was subsequently extended towards SSI using two fictive embedded receivers with different embedment depths. Fully coupled FE models were used as numerical references and compared with engineering spring-dashpot, uncoupled numerical impedance and coupled numerical impedance formulations. The main differences between the SSI approaches occurred in response amplitude rather than dominant frequency. Within the investigated interface discretisations, the engineering and uncoupled formulations showed the most consistent agreement with the fully coupled references. The uncoupled formulation showed little sensitivity to interface refinement, whereas the coupled formulation was more sensitive to segment size. Refinement improved several coupled response components, although formal convergence was not established.

The results demonstrate a structured approach for predicting the transmission of construction-induced vibrations through the source-soil-receiver chain when source and dynamic soil information are limited. The SSI comparison is methodological rather than building-specific, as the fictive axisymmetric receivers do not represent the actual TNW structure. Further measurements, improved dynamic soil characterisation and building-specific three-dimensional modelling are required for quantitative predictions of vibration levels inside TNW.