The near catastrophic failure of Whaley Bridge dam that featured in the news during August 2019 has emphasised the need for the routine high-quality inspection of dam structures and reservoirs. Visual inspections can identify obvious cracks and surface defects; but what about hidden defects?
As highlighted in the devastating Whaley Bridge dam failure, Water Engineers face a real problem in identifying, repairing and maintaining weaknesses in dam structures. Visual defects are readily identifiable and can be dealt with before the problem escalates. However, a significant problem is ensuring structural integrity where visual clues indicating serious defects aren’t present. The careful maintenance and repair of dams must also consider the potential destructive impact on the local area and members of the public. But how can you identify what the eye cannot see?
Help is at hand in the form of geophysics. One of the modern, high-tech tools at the disposal of SUMO Geophysics is ground penetrating radar (GPR). This geophysical survey method has become a mainstream technique for the non-destructive testing of engineering structures. This includes the NDT testing of barrages, weirs, locks and dams.
SUMO’s GPR surveys are particularly useful for locating voids beneath the concrete elements of a dam or reservoir that would not be revealed by routine visual inspection. A grid of profiles can be carried out over crucial parts of the spillway. This could include the tumblebay, chute and stilling basin.
The outcome of SUMO’s GPR surveys is that any identified voids or geophysical anomalies are plotted in an engineering compatible format. This has been carefully developed to be readily understandable by a range of engineering professionals. It allows for a smoother preparation for a programme of remedial action before failure occurs.
