Computation of ground waves from pile driving and their effects on structures
Present guidance on levels of vibration generated by pile driving is primarily empirical, conservative and often contradictory. The objective of this research was to model the ground waves generated by pile driving using the ABAQUS finite element program in order to predict the free ground surface response resulting from installation by both impact and vibratory hammers. New procedures including infinite element and quiet boundary formulations have been developed for the computation of ground surface vibrations caused by impact and vibratory driving of pre-formed piles. The procedures do not require a detailed knowledge of site conditions and are therefore particularly useful as a preliminary design tool and for modelling the large amount of site data that currently exists in order to assist in the development of more rational guidance. The work has brought together research from several areas of study in order to produce computational procedures for modelling vibrations from pile driving. The new models have been validated by comparisons with measurements from various piling sites. The new methods now need to be applied to a large number of varied sites in order to develop site specific guidance. It is envisaged that this guidance could be in the form of design charts or simple formulae for incorporation into the relevant British Standards or Eurocodes. A range of common building forms has been incorporated into the models. The results indicate that slender frames can be analysed by transient displacements imposed on the foundations; however, a full three-dimensional analysis with soil-structure interaction is required for walls and infilled panels so that the reduced foundation displacements are modelled correctly. The techniques developed during this project could be usefully extended to model the effects of pile driving on various geotechnical structures and pipelines and also other forms of excitation, such as vibrocompaction.