Methods of estimating the acoustic parameters of ground

A method for determining the dynamic and dissipative characteristics of the ground (velocities and attenuation coefficients of elastic waves) in urban environments is presented. The knowledge of these characteristics is necessary for estimating and monitoring environmental conditions in the presence of intense sources of sound and vibration. Such problems arise in connection with prediction of vibration levels produced on the around surface by underground and surface sources (transportation, construction machinery, etc.). With allowance for the specific features of solving direct problems of elastic wave field calculation, inverse problems of the tomography of ground are formulated and methods of their solution are described. Several algorithmic realizations based on multiply solving the direct problem and also on expanding the total field in generalized spectral components are considered. The latter approach makes it possible to simplify the estimation of parameters by applying the minimization of the residual functional. The basis functions used for approximating the experimental data are chosen in the form of Jacobi polynomials. (C) 2004 MAIK "Nauka/Interperiodica".