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Título del libro: Deformation Characteristics Of Geomaterials
Título del capítulo: Seismic Wave Velocities of Soft Clays Measured with Piezoelectric Crystals in an Oedometer

Autores UNAM:
EFRAIN OVANDO SHELLEY;
Autores externos:

Idioma:

Año de publicación:
2015
Palabras clave:

Wave velocity; near field effect; excitation frequency; transfer function; system's fundamental frequency


Resumen:

We present some of the results of an experimental investigation aimed at characterizing soil samples in terms of seismic wave velocities estimated from measurements with piezoelectric crystals. Specimens of Mexico City Clay were mounted on an instrumented consolidometer in which we obtained compression and shear wave velocities. The paper examines the close field effect on shear wave velocity measurements by looking at the signals recorded in the piezoelectric receivers in response to sinusoidal signals induced at different frequencies that ranged between 1 and 7 kHz. We use the specimens' transfer functions to obtain their natural frequencies; with them and with a dimensionless parameter (the quotient of the distance between the emitter and the receiver and wave length), we put forth a procedure to determine the minimum frequency required to avoid near field effects and, hence, to obtain reliable values of shear wave velocities.


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