A fast inversion analysis algorithm for the spectral analysis of surface wave (SASW) method

Spectral Analysis for Surface Wave (SASW) is a widely practiced NDT method due to its ability to identify the shear velocity profile of subsurface layers. However, the SASW method is limited to point-to-point inspection because all data has to go through an inversion process, which is iterative and manual. Some automated iteration techniques were developed to improve the efficiency of inversion analysis. These attempts did not change the situation much because they were still based on the guess-and-check procedure incorporated with a forward analysis. In this paper, a new inversion analysis algorithm is proposed to estimate the shear velocity profile rapidly without performing conventional forward analysis. Unlike conventionally determining the dispersion curve with a stiffness matrix or something similar, the dispersion curve of a layered structure is assumed to be a weighted combination of the shear velocity profile. The weighting factors are determined according to the variation of particle displacement with depth for a specified wavelength of surface wave. Based on this assumption, a fast inversion algorithm is established to estimate the shear velocity profile from a given dispersion curve. No prior knowledge of the test site or personal expertise is needed because this method does not require the initial values of the layer depths and shear velocities. This new method allows the SASW method to be a fully automatic or even real-time reporting method for highway pavement detection. The accuracy of this fast inversion algorithm is verified by comparing the results to those of the conventional algorithm.

[1]  Kenneth H. Stokoe,et al.  EFFECTIVENESS OF GROUND IMPROVEMENT FROM SPECTRAL ANALYSIS OF SURFACE WAVES. , 1983 .

[2]  N. Al-Shayea,et al.  NONDESTRUCTIVE TESTING OF CONCRETE STRUCTURES USING THE RAYLEIGH WAVE DISPERSION METHOD , 1996 .

[3]  John S. Popovics,et al.  Non-contact detection of surface waves in concrete using an air-coupled sensor , 2002 .

[4]  J. W. Dunkin,et al.  Computation of modal solutions in layered, elastic media at high frequencies , 1965 .

[5]  Jinying Zhu,et al.  Non-Contact NDT of Concrete Structures Using Air -Coupled Sensors , 2006 .

[6]  Dario Albarello,et al.  Combining genetic and linearized algorithms for a two-step joint inversion of Rayleigh wave dispersion and H/V spectral ratio curves , 2007 .

[7]  S. Nazarian,et al.  In situ determination of elastic moduli of pavement systems by spectral analysis of surface waves method (theoretical aspects) , 1985 .

[8]  Nils Ryden,et al.  Fast simulated annealing inversion of surface waves on pavement using phase-velocity spectra , 2006 .

[9]  M. Catalina Orozco,et al.  Inversion Method for Spectral Analysis of Surface Waves (SASW) , 2004 .

[10]  Jianghai Xia,et al.  Estimation of near‐surface shear‐wave velocity by inversion of Rayleigh waves , 1999 .

[11]  Osama Hunaidi,et al.  Inversion of SASW dispersion curves based on maximum flexibility coefficients in the wave number domain , 2006 .

[12]  Tae-Ho Kang,et al.  Accelerated Stiffness Profiling of Aggregate Bases and Subgrades for Quality Assessment of Field Compaction , 2006 .

[13]  Di Yuan,et al.  Rapid determination of moduli with spectra-analysis-of-surface-waves method , 1995 .

[14]  Eduardo Kausel.  Fundamental Solutions in Elastodynamics: Fundamentals , 2006 .

[15]  Richard D. Miller,et al.  Multichannel analysis of surface waves , 1999 .

[16]  F. E. Richart,et al.  Vibrations of soils and foundations , 1970 .

[17]  Shahram Pezeshk,et al.  A New Inversion Procedure for Spectral Analysis of Surface Waves Using a Genetic Algorithm , 2005 .