Staggered and intermittent geofoam-infilled trenches for passive vibration mitigation

This paper examines the effectiveness of different geofoam-infilled trenches (GT) in mitigating ground-borne vibrations under passive vibration screening (PVS) conditions. Owing to the substantial cost of continuous geofoam-infilled trenches (GTC), the present work investigates the efficacy of discontinuous geofoam-infilled trenches, including intermittent (GTI) and staggered (GTS) configurations, to mitigate ground-borne vibrations under PVS conditions through full-scale field experiments. A modular system comprising prefabricated panels is adopted for installing GT, enabling untroubled installation, removal, reuse, and customisation. The frequency-dependent performance of OT and GT under PVS conditions to be thoroughly evaluated. Experimental findings indicate that the performance of GTI and GTS is comparable to that of the open trench (OT) at higher input frequency (fi). The effectiveness of all trenches increases with increasing fi. However, at lower fi, OT and various GT configurations are found to be ineffective in mitigating vibrations at locations far beyond the trench. Furthermore, regression analysis is used to establish a simplified design equation to predict the effectiveness of various GT configurations.