Ground Vibrations near Buried Structures due to the Installation of Rockfill Columns

Environmental considerations are an important aspect of construction activities, such as the impact of construction vibrations at project sites and in nearby properties. There are limited studies to investigate the impact of vibration from ground improvement construction and how underground utilities can be protected from vibration damage. This research is aimed at developing empirical formulations that can be used to predict ground particle velocities near buried structures. This will allow engineers to minimize potential vibratory damage to buried structures. In this study, ground vibrations are produced by the installation of rockfill columns, a ground improvement technique to stabilize riverbanks. Installation of rockfill columns was done near a buried aqueduct. So, there is a concern that this aqueduct can be damaged by ground vibrations. Finite-element analysis was done to provide information on ground vibrations caused by the installation of rockfill columns. The finite-element models were calibrated with particle velocities measured at the construction site. Results showed that the particle velocities obtained in the numerical models correlated well with the measured particle velocities and those reported in the literature (although from different sources of vibrations). Empirical relationships are proposed between ground vibrations and their impacts on nearby buried structures.

Limiting ground vibration on structures near construction sites is a challenging task. Even though most guidelines use peak particle velocity (PPV) as the limiting parameter, there is no consensus as to which limiting values to use. Ideally, project-specific values could be estimated with predicting equations. Estimation of the vibratory impact from the installation of rockfill columns in the ground and their impact on buried structures is limited in the literature. This is due to the lack of data to validate prediction methods. As is shown in this paper, numerical results in this research reasonably agree with field PPVs reported in the literature. Therefore, empirically based predictions for the installation of rockfill columns, for the removal of steel casings, and for the vibratory impact of ground vibrations on buried structures for 5%, 50%, and 95% exceedances are proposed in this study. It is recommended that the proposed empirically based predictors be used as a preliminary evaluation tool, preceding numerical simulations to predict expected ground vibration in terms of PPV. It is understood that when the field data are obtained in the near field but prediction is for far field, the predictions tend to be conservative. On the other hand, prediction for the near-field response based on data from the far field is inappropriate and should be used with caution. In the field, well-planned instrumentation and monitoring would help protect buried structures from potential damage from ground vibrations, which was done in the case study presented in this paper.