1 / 28

The Use of MASW in the Assessment of Soil Liquefaction Potential

The Use of MASW in the Assessment of Soil Liquefaction Potential. Chih-Ping Lin C-C Chang, I-L Chen, T-S Chang National Chiao Tung University, Taiwan November 4, 2003. Outline. Backgrounds Multi-channel Analysis of Surface Wave Verification Case 2-D Imaging of Liquefaction Potential

cyma
Download Presentation

The Use of MASW in the Assessment of Soil Liquefaction Potential

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. The Use of MASW in the Assessment of Soil Liquefaction Potential Chih-Ping Lin C-C Chang, I-L Chen, T-S Chang National Chiao Tung University, Taiwan November 4, 2003

  2. Outline • Backgrounds • Multi-channel Analysis of Surface Wave • Verification Case • 2-D Imaging of Liquefaction Potential • Summary

  3. Acknowledgement • Funding for this research was provided by the National Science Council and Institute of Planning & Hydraulic Research.

  4. Field Tests for assessing liquefaction potential • Standard Penetration test(SPT) • Cone Penetration Test(CPT) • Shear Wave Velocity Measurements (SWV) • Vs vs. Liquefaction resistance • Effects of large particles minor • Non-invasive method can be used • Can be measured in the lab and in-situ • Directly related to Gmax required for site response 1 2 3 4 5

  5. Shear Wave Velocity Measurements • Cross-hole • Down hole • Seismic cone • Suspension PS-logger • Surface wave method • Non-invasive • Efficient • Cost effective 1 2 3 4 5

  6. Basic Principle of Surface Wave Method 1 Frequency component Geophones 2 VS VS1 3 4 VS2 5 VS3 z Dispersion curve Field Testing V Dispersion analysis Inversion f

  7. Surface Wave Methods • Two-station methods • Steady-state Rayleigh wave method (SSRW) • Spectral analysis of surface wave (SASW) • Multi-station Method • Phase-offset regression (MSASW) • Multi-station wavefield transformation of surface wave (MWTSW) 1 2 3 4 5

  8. SASW Method 1 Df 2 3 4 5 Unwrapping infdomain Df v f f

  9. l = 2p/k T = 2p/w v 1 Multi-station Data Acquisition 1 u(tm,xn) Measurement: f =10, v = 200 m/s 2 3 4 5 t t-x domain x

  10. Df l Dx 2p Unwrapping in xdomain f-x domain MSASW Method 1 DFT w.r.t. time domain 2 3 4 5 f f R2 x

  11. MWTSW Method k 1 DSFT w.r.t. space domain 2 3 t-x domain 4 5 f-x domain f-k domain f-v domain

  12. Multi-station Analysis of Surface Wave 1 0 1 N-2 N-1 2 x0 Dx L 3 :Source 4 :Geophone 5

  13. Multi-station Wavefield Transform 1 2 3 4 f-k f-p 5 f-l f-v

  14. Verification Case - Site 1 2 3 4 5

  15. Seismic Equipment 1 2 3 4 5

  16. Verification Case – Field Testing 1 2 3 4 5

  17. Verification Case – Dispersion AnalysisDx = 0.5 m, L = 11.5 m 1 2 3 4 5

  18. Verification Case – Dispersion AnalysisDx = 1 m, L = 23 m 1 2 3 4 5

  19. Verification Case – Dispersion AnalysisDx = 1 m, L = 23 m 1 2 3 4 5

  20. Verification Case – Inverse Analysis 1 2 3 4 5

  21. Verification CaseVs and FS against liquefaction 1 2 3 4 5

  22. Surface Wave Seismic Imaging 1 2 3 4 5

  23. Surface Wave Seismic Imaging 1 2 3 4 5

  24. Surface Wave Seismic Imaging 1 2 3 4 5

  25. Andrus and Stokoe (2000) 1 2 3 4 5

  26. Summary Advantages of MASW • Field testing simple & efficient • Multi-station redundancy • Automation: site quality control • Robustness: dispersion curve visualized • 2-D imaging 1 2 3 4 5

  27. Summary The results show that the MASW • efficient, cost effective, and non-invasive • useful in gravelly soils • effective for ‘first look’ or investigation of lateral variations Further Research • Lateral resolution • Inversion and vertical resolution 1 2 3 4 5

  28. Thank You! Chih-Ping Lin Geotechnical Engineering Group National Chiao Tung University

More Related