Application of nondestructive evaluation techniques on concrete dams

Geophysics and the search of freshwater bodies: A review

“…From this date it has been accepted that the acoustic energy wave's travel through the subsurface can be likened to that first noticed in the mercury containers by Mallet, i.e., 'hemispherical propagating waves' [16]. Seismic reflection and refraction use acoustic wave (short duration and constant frequency) propagation to measure changes in acoustic impedance [17]. Seismic waves travel through the subsurface as body waves, whilst they travel along the Earth's surface as surface waves.…”

“…Changes are detected by piezoelectric transducers or hydrophones on the surface where they are then converted to frequency, filtered and displayed. Wave reflections are ultimately caused by '…sudden change in elastic properties or density of a medium, i.e., change in acoustic impedance' [17]. The success of seismic reflection profiling is dependent on a frequency selection that best fits the research objective [20].…”

Crack detection in concrete gravity dams using a genetic algorithm

“…In 1992, a new procedure was presented to allow a consistent and rational transition from the linear frequencydomain model of concrete gravity dam-foundation-reservoir systems to time-domain models suitable for non-linear seismic analysis (Leger and Bhattacharjee, 1992). Other investigators studied the application of non-destructive evaluation techniques on concrete dams (Hassani et al, 1997). They presented the theoretical and practical aspects of the miniature seismic reflection (MSR) system for the evaluation of concrete dams.…”