Consideration of Cavity Detection Applicability of SASW Technique Through the Model Test

This paper presents a detection technique for determination of the cavity existence under slab track of railway. The detection technique is based on the Spectral Analysis of Surface Wave (SASW) test. The SASW test is a non-destructive seismic method which uses Rayleigh-type waves to measure in situ shear wave velocity (Vs) of soil. It is found form field model tests that underground obstacles or buried objects and soil heterogeneity significantly affect surface (Rayleigh) wave dispersion. Cavities and obstacles looser than the surrounding soil cause a decrease in the shear wave velocity. The theoretical background and field implementation procedures of using SASW for detecting cavity below the slab track are explained.