Shear wave velocity in down-hole seismic tests: Equipment and factors affecting the test data

Osvaldo Paiva Magalhães Vitali, Rubens Antonio Amaral Pedrini, Heraldo Luiz Giacheti

In the proceedings of: GEO2011: 64th Canadian Geotechnical Conference, 14th Pan-American Conference on Soil Mechanics and Geotechnical Engineering, 5th Pan-American Conference on Teaching and Learning of Geotechnical Engineering

Session: In Situ Testing

ABSTRACT: The maximum shear modulus (Go) is an important dynamic soil parameter in the geotechnical engineering design that can be calculated based on the shear wave velocity (Vs) measurement. Cross-hole and down-hole tests can be used to measure Vs. According to the literature, the seismic piezocone test has proven to be a fast, economical and reliable method to determine Go. It is assumed that down-hole and cross-hole tests have similar results. This paper briefly describes a system developed to perform the down-hole test right after the CPTU, using the same hole. In spite of all the advantages of down-hole tests, recording and interpretation of seismic data are not so simple. The test procedure and its interpretation for the developed system are presented herein to ensure the quality of measured Vs values, pointing out the most concerning aspects of the test.

RESUMEN: El módulo de corte máximo (Go) es un parámetro dinámico de los suelos importante en diseños geotécnicos que se puede calcular a partir de la medida de la velocidad de la onda de corte (Vs). Los ensayos cross-hole y down-hole pueden ser utilizados para medir Vs. De acuerdo con la literatura, los ensayos de piezocone sísmico se han mostrado un método rápido, económico y confiable para determinar Go y se puede asumir que los ensayos down-hole y cross-hole conducen a resultados similares. En este artículo se describe brevemente un sistema desarrollado para realizar ensayos down-hole luego después de la realización de un ensayo CPTU, utilizándose la misma perforación. A pesar de todos los beneficios de lo ensayo down-hole, el registro y la interpretación de dados sísmicos no son tan sencillos. En este trabajo, se presenta el procedimiento del ensayo y su interpretación para el sistema desarrollado para garantizar la calidad de los valores de Vs medidos, destacándose los aspectos más preocupantes del ensayo.

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Cite this article:
Osvaldo Paiva Magalhães Vitali; Rubens Antonio Amaral Pedrini; Heraldo Luiz Giacheti (2011) Shear wave velocity in down-hole seismic tests: Equipment and factors affecting the test data in GEO2011. Ottawa, Ontario: Canadian Geotechnical Society.

@article{GEO11Paper334,author = Osvaldo Paiva Magalhães Vitali; Rubens Antonio Amaral Pedrini; Heraldo Luiz Giacheti ,title = Shear wave velocity in down-hole seismic tests: Equipment and factors affecting the test data,year = 2011}