Application of full-waveform inversion technology for the detection of dam structural anomalies: A case study in Western China

ABSTRACT Geophysical methods play a crucial role in noninvasive dam monitoring, but traditional techniques often face limitations in resolution, depth penetration, and lateral variation detection, which hinder their effectiveness for structural assessments. To address these challenges, we apply full-waveform inversion (FWI) to a 375 m long dam profile to evaluate its potential for structural imaging and future monitoring. Seismic data are pre-processed by stacking shots to enhance the signal-to-noise ratio (S/N), followed by band-pass and f-k filtering to remove linear and zero-frequency noise. Notch and median filtering are then applied to reduce residual noise, and time windows are used to separate surface-wave signals. FWI successfully reconstructs a detailed shallow S-wave velocity profile but yields suboptimal results for P-wave velocity, as the primary inverted signals are surface waves. The final inversion results identify the key regions and interfaces within a depth of 35 m, as well as three high-velocity anomaly zones associated with embedded monitoring equipment at a depth of 10 m. In contrast, the multi-channel analysis of surface waves method, although capable of identifying general subsurface features, fails to resolve these high-velocity anomalies with the same level of detail and precision. These results highlight the advantages of FWI in providing higher-resolution imaging and detecting subtle anomalies for future dam monitoring.