Development and Validation of an Updated System for Down-hole Seismic Testing together with Piezocone

Abstract

This paper presents the updated version of a system that uses a probe and software to carry out down-hole seismic testing in conjunction with piezocone to determine shear wave (V_s) and compressional wave (V_P) velocities for geotechnical site characterization. The system was used in down-hole tests carried out at experimental research sites located in the interior of the state of São Paulo, Brazil, where reference V_s and V_P values determined by cross-hole and down-hole tests are available. The updated seismic probe has six geophones: three for S wave recordings spaced 0.5 m apart and three for P wave recordings, also spaced 0.5 m apart. The updated software integrates data acquisition, allows the visualization of S and P wave traces and calculates V_s using the true interval method. The V_P profiles could only be determined by the pseudo-time interval using commercial software. The developed system is considered efficient for determining V_s profiles in the way it was used. Further studies are needed to better understand the propagation of P waves, as well as to improve the system and the method for determining V_P profiles.