Field Experiments on Wave Propagation and Vibration Isolation by Using Wave Barriers

In this paper, the obtained results from the experimental studies describe the basic characteristics of wave propagation and ability of possible measures to reduce the impact of soil vibrations on structural response for both active and passive isolation cases. A series of field tests on the foundation vibrations generated by electrodynamic shaker are performed to examine the screening efficiency of open and in-filled trench barriers which are constructed for full-scale measurement. From field measurements of amplitude with and without the barrier, the amplitude reduction ratio is estimated at different points of interest. Wave propagating characteristics and frequency-dependent screening effects of the wave barriers are investigated according to various isolation material stiffnesses. The remarkable outcomes from these experimental studies can be briefly generalized as follows: backfilled trench with softer material than soil is more effective for the passive isolation than the active one. The reduction effects of wave barriers depend on the frequency of vibration source for both passive and active isolation cases. In-situ measurements confirm that vibration screening systems using open or in-filled trench barriers can be applied as a reduction measure for soil vibrations due to a moving load which is considered as stationary wave source in this problem.