Field and numerical modelling of sand-rubber mixtures vibration barrier

Reducing ground vibrations using a vibration barrier has shown mixed levels of success in practice. The factors affecting the success are the source frequency, distance of source to area of interest at which vibration is to be reduced, ground type, barrier dimensions, and barrier material. Open trench has been shown to be the most effective vibration barrier but faces practical problems in implementation. To overcome the open trench problem, materials like air-filled cushion, polystyrene/geofoam, composites and piles have been used. One promising material which has not been investigated in the field for use as a vibration barrier is sand-rubber mixture. In this study, field tests using a continuous vibration source at various frequencies were conducted where the vibration amplitudes behind an open trench and two different sand-rubber mixtures barriers were measured. The amplitude ratios for the different vibration barriers were compared. The field tests were also modelled numerically to provide contours of the amplitude ratio around the vibration barrier to better understand the spatial performance of the vibration barrier. The sand-rubber mixture barrier is able to reduce the vibration amplitude by 75% behind the barrier when depth of barrier to Rayleigh wavelength ratio is ≥ 0.7. For a barrier, there is a finite zone behind the barrier where the amplitude ratio is ≤ 0.25. The size of the “effective” zone decreases as the impedance of the barrier increases.