Importance of coherence between geophysical and geotechnical data in dynamic response analysis

Abstract

The demand for a precise evaluation of shear wave velocity Vs, is gaining interest in the field of geotechnical engineering due to its importance as a key parameter required to properly evaluate typical characteristics of soils. Nowadays, Vs measurements are performed on the field using different methods, such as SCPT tests and various geophysical methods. However, the effectiveness of these field measurements is not guaranteed and rather depends on how they are analyzed. Furthermore, a proper analysis is critical since the collected data may be used in liquefaction evaluation or earthquake ground response analyses. In these situations, it is recommended to verify the coherence between the obtained geophysical (Vs) and geotechnical (N-SPT, qc-CPT) measurements using alternative methods (e.g., Vs-correlations, H/V method, etc...). In some situations, the correlation between the different measurements makes it easier to unambiguously define seismic wave profiles. In other cases, geophysical and geotechnical tests would provide different resolutions for Vs measurements, an issue that complicates the decision of the practitioner. In this paper, we first demonstrate the importance of the shear-wave velocity in liquefaction potential analysis. A case study performed in eastern Canada is also presented where we show the importance of the method used to calculate Vs profiles (MASW, MMASW).