Optimisation of receiver’s location in bender element experiments using computational wave filtration

Abstract

Bender elements are shear wave transducers, used for the computation of small strain shear moduli of geomaterials. However, the distortion of the output signal caused by residual compression waves may lead to important errors in the shear modulus estimates. We present a novel procedure for the optimisation of the location of the receiver bender element, to avoid regions where the distortion of the output signal is strong, without compromising the strength of the shear wave signal. The procedure is based on a computational technique naturally able to distinguish between the compression and shear waves present in the seismic response of geomaterials. This property enables the construction of compression and shear amplitude maps, that can be used to decide the best location for the receiver prior to running the experiment. The experimental validation of the procedure confirms that it leads to output signals which are easier to interpret than those obtained with the transmitter and receiver in the conventional, tip-to-tip configuration.