Surface Wave Method as Applied to Geotechnical Site Investigation and Pavement Evaluation

摘要

Seismic surface waves exhibit distinguishable dispersion characteristics for different geotechnical sites or pavement structures and thus the surface wave method has been used in site investigation and pavement evaluation. Effects of measurement errors, depth resolution and separation of different structural parameters are the three major aspects to be concerned with this method. With the aid of simple concepts and examples, it shows that the measurement errors have a direct impact on all the three aspects and that the depth resolution, the accuracy of structural parameter estimates and the separation of different structural parameters are three competing objectives which are related reciprocally. The study of measurement errors and depth resolution can be useful for selecting the model to be inverted and for evaluating the reliability of the inversion result. In most cases, use of the dispersion data consisting of the fundamental-mode Rayleigh wave phase velocities only may resolve a structure of up to 4 to 5 layers, depending on the measurement error and the structural feature. This situation is independent of the method or algorithm adopted in data analysis.