Evaluating the Integrity of Slab–Soil Contact with Impulse Response Testing: Insights from Numerical Simulations

To assess the sensitivity of impulse response testing to potential poor support zones or voids beneath the foundation slabs, numerical simulations were performed using the finite element method. These simulations covered a range of scenarios, including soil-loosening zones, sub-slab cavities, and slab cracks. The analysis of the simulation results employed two distinct techniques: the normalized acoustic response method and the ASTM C1740 mobility spectrum approach. These methods allowed the parameters and attributes derived from changes in input signals to be described in relation to the specifications within the synthetic models.