Utilization of multimode surface wave dispersion for characterizing roadbed structure

摘要: Abstract Accurate measurement of shear (S)-wave velocity in a roadbed subsurface with reversal is crucial as well challenging. A high frequency Rayleigh wave survey was carried out on site from Henan, China to determine S-wave velocities approximately 15 m depth. The phase shift approach used directly construct high-resolution image multimode dispersion curves the frequency–velocity (f–v) domain multi-channel raw shot gather signal-to-noise (S/N) ratio. measured fundamental and two higher-mode were then inverted by genetic algorithms reconstruct fine structure tested subsurface. Our case study demonstrates that an inversion performed only mode data limited resolution degree error may yield unrealistic model. better agreement direct borehole measurements, however, obtained when second-mode are simultaneously data, which clearly reveals 1-m thick softer soil layer between stiff layers roadbed. higher accuracy profile achieved incorporating three modes into process. This representative highlights advantages fully exploiting intrinsic multimodal properties waves greatly enhances our confidence accurately imaging characterizing complex