Full Waveform Inversion of a Synthetic Florida Limerock Specimen

We have constructed a one-meter cubical model made of low-strength concrete that simulates Florida limerock in which to test a new geophysical instrument. In the experiment reported, we used an instrumented hammer to apply a pulse load at one corner of the top surface. The resulting accelerations were recorded using a string of receivers placed along a diagonal line of the top surface and these waveforms were inverted using an ABAQUS-based inversion model to determine the elastic properties of the specimen. To reduce computing time, the three-dimensional cube was represented in ABAQUS using an axisymmetric model and the inversion routine used a regularized Gauss–Newton iteration algorithm. To provide independent corroboration, the modulus results from the inversion were compared with modulus values computed from free-free resonant column test data collected from cylindrical samples of the synthetic limerock used to construct the cube specimen. The modulus properties from both techniques were found very similar to one another.