2007 Volume 60 Issue 4 Pages 305-313
A trench is sometimes used in order to cut down the ground vibrations caused by traffic, construction works, and factory machines. The shielding effect of vibrations by a trench has been often examined by laboratory experiments using ultrasonic waves and field experiments. Recent developments of personal computers enhance use of numerical analysis. In this study, DEM (discrete element method) is adopted for simulation tool. The reduction ratio of Rayleigh waves after passing through a narrow trench had been proposed by Yoshii (1971) and it is the function of the trench depth. Our simulation results can reproduce this behavior very well. In case of a wide trench, however, there is no empirical relationship describing the reduction behaviors. In this paper, we propose a new equation for Rayleigh wave reduction including the depth and width of a trench based on simulation studies.
