Assessing vibration isolation performance of single and coupled wave barriers through field experiments

Wave barriers have become a common practice in the mitigation of undesired ground vibrations when direct isolation of the source has not been applicable. Even though the vibration isolation performance of open and in-filled trenches has been scrutinized, only a limited number of experimental studies are available about stiff wave barriers such as piles and sheetpiles. The present study aimed at assessing not only the screening effectivenesses of single barriers such as open trench and sheetpile but also the coupled open trench-sheetpile barrier. 15 m long, 0.75 m wide, 3 m deep single open trench and 15 m long, 8 m deep sheetpile were investigated in full-scale vibration tests. The influences of excitation frequency, source-barrier distance and barrier type on the vibra-tion isolation were examined. The efficacy of the single and coupled-wave barriers was quantitatively presented within a wide range of frequencies (10-80 Hz) based on field measurements using highly sensitive accelerom-eters and geophones. No vibration isolation was provided at the excitation frequency of 10 Hz, while all the wave barriers provided an appreciable amount of reduction in the amplitudes of the vibrations at other frequencies. In most of the test configurations, the open trench and the coupled-wave barrier exhibited similar isolation per-formance and outperformed the sheetpile. In cases the sheetpile has already been installed, the implementation of an open trench in front of the sheetpile may noticeably improve the screening effectiveness.