Asymptotic analysis of hard wave barriers in soil

A simple analytical model is developed to predict the vibration isolation of a hard wave barrier (e.g. filled trench, screen of piles, etc.). The model is, moreover, restricted to asymptotic conditions of high frequencies and soft soils. While the soil's surface wavelength is therefore short, barrier hardness' implies much longer wavelengths downward along the barrier itself. These conditions permit a number of approximations: the distributed excitation of the barrier by the surface waves is replaced by a concentrated force; the energy passing underneath the barrier is ignored in favor of that re-radiated by the barrier motion itself; and that radiation is approximated as if the barrier were rigid and semi-infinite. Subsurface soil-barrier interaction is accounted for in the barrier dynamic stiffness; both single degree-of-freedom and flexible models are considered. Successful comparisons are,made to numerical results from the literature, as well as field measurements near a railway track. (C) 2003 Elsevier Science Ltd. All rights reserved.