Estimation of the Soil Layers Thickness Using Multi-Chanel Analysis of Surface Waves and Surface Wave Dispersion Curve

Document Type : Original Article

Authors

1 Ph.D. Candidate, Department of Civil and Environmental Engineering, Shiraz University of Technology, Shiraz, Iran

2 Assistant Professor, Department of Civil and Environmental Engineering, Shiraz University of Technology, Shiraz, Iran

3 Associate Professor, Department of Civil and Environmental Engineering, Shiraz University of Technology, Shiraz, Iran

Abstract

One of the most interesting topics in the geotechnical and geophysical engineering is the use of surface waves to characterize the earth subsurface layers. In a vertically heterogeneous media, the phase velocity of the surface wave is a function of the frequency (the frequency-phase velocity relationship is called dispersion curve). The dispersion curve is calculated by the shear wave velocity, compressive velocity, density, and thickness of each of the layers, which their properties can be increasing or decreasing from the surface to the half-space. In this paper, horizontal soil layers were modelled using finite element method based software (ABAQUS). Due to the different layering specifications, the models are divided into two main types: the layers’ characteristics increase with depth and the layers' characteristics decrease and increase with depth. An active impact source was used to create surface waves and the absorption layers with increasing damping (ALID) were applied to the model boundaries to prevent the wave reflection. Based on the gathered surface wave data, the dispersion curve was plotted using Frequency-Wavenumber Transfer method. In addition, the effects of different geophone offsets on the dispersion curve were investigated. The results showed that using the dispersion curve and phase velocity at high frequencies, the thickness of the surface layer can be calculated. Also, the slope of the dispersion curve at low frequencies indicates the number of the layers at different properties, and the steeper and closer to the vertical, means that a few number of layers are exist in the media. Furthermore, the effects of different geophone offsets were investigated and it was observed that geophone offsets should be limited to less than one-fourth of the layer depth in order to prevent the dispersion curve jumping to the higher modes. Furthermore, if the dispersion curve jumps to the higher modes at high frequencies, seismic data can be taken at a less geophones’ offset or the dispersion curve frequency range limitation is only before jumping to higher modes.

Keywords

References

[1] Aki, K. and P.G. Richards, Quantitative seismology. 2002.
[2] Anderson, J.G., Strong-motion seismology. INTERNATIONAL GEOPHYSICS SERIES, 2003. 81(B): p. 937-966.
[3] Pei, D., Modeling and inversion of dispersion curves of surface waves in shallow site investigations. Vol. 68. 2007.
[4] Hashemi Jokar, M., J. Boaga, L. Petronio, M.T. Perri, C. Strobbia, A. Affatato, R. Romeo, and G. Cassiani, Detection of lateral discontinuities via surface waves analysis: a case study at a derelict industrial site. Journal of Applied Geophysics, 2019: p. 65-74.
[5] Scales, J.A. and A.E. Malcolm, Laser characterization of ultrasonic wave propagation in random media. Physical Review E, 2003. 67(4): p. 046618.
[6] Strobbia, C., J. Boaga, G. Cassiani, M. Hashemi Jokar, and P. Primiero, Integrated seismic characterization for deep engineering targets: active and passive surface waves, reflection and refraction near-surface modelling from a single acquisition. International Conference on Engineering Geophysics, Al Ain, United Arab Emirates, 2017.
[7] Schwenk, J.T., S.D. Sloan, J. Ivanov, and R.D. Miller, Surface-wave methods for anomaly detection. Geophysics, 2016. 81(4): p. EN29-EN42.
[8] Foti, S., C.G. Lai, G.J. Rix, and C. Strobbia, Surface wave methods for near-surface site characterization. 2015: CRC Press.
[9] Neducza, B., Stacking of surface waves. Geophysics, 2007. 72(2): p. V51-V58.
[10] Hashemi Jokar, M., H. Rahnema, J. Boaga, G. Cassiani, and C. Strobbia, Application of Surface Waves for Detecting Lateral Variations: Buried Inclined Plane. Near Surface Geophysics, 2019: p. 1-45.
[11] Lowe, M., R. Challis, and C. Chan, The transmission of Lamb waves across adhesively bonded lap joints. The Journal of the Acoustical Society of America, 2000. 107(3): p. 1333-1345.
[12] Hesse, D. and P. Cawley, Surface wave modes in rails. The Journal of the Acoustical Society of America, 2006. 120(2): p. 733-740.
[13] Castaings, M., C. Bacon, B. Hosten, and M. Predoi, Finite element predictions for the dynamic response of thermo-viscoelastic material structures. The Journal of the Acoustical Society of America, 2004. 115(3): p. 1125-1133.
[14] Luo, W. and J.L. Rose, Phased array focusing with guided waves in a viscoelastic coated hollow cylinder. The Journal of the Acoustical Society of America, 2007. 121(4): p. 1945-1955.
[15] Drozdz, M.B., Efficient finite element modelling of ultrasound waves in elastic media. 2008, Imperial College London.
[16] Lin, S., Advancements in active surface wave methods: modeling, testing, and inversion. 2014.
[17] ABAQUS v6.14, S., Abaqus Analysis User’s Guide. Dassault Systèmes Simulia Corp., Proidence, RI, USA,  www.simulia.com, 2014.
[18] Motamed, R., K. Itoh, S. Hirose, A. Takahashi, and O. Kusakabe. Evaluation of wave barriers on ground vibration reduction through numerical modeling in ABAQUS. in Proceedings of the SIMULIA Customer Conference 2009. 2009.
[19] Atkinson, J., Non-linear soil stiffness in routine design. Géotechnique, 2000. 50(5): p. 487-508.
 

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History

  • Receive Date: 24 June 2019
  • Revise Date: 29 July 2019
  • Accept Date: 27 August 2019

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