Issue << content << Complex of NDT Methods for Cavities Detection under Fastening Plates of Channels Ground Slopes. Methodical Features of Application


DOI:

2015. . No. 2(68) - Jun 2015, pp. 16-21

Complex of NDT Methods for Cavities Detection under Fastening Plates of Channels Ground Slopes. Methodical Features of Application

V. V. Glazunov, V. C. Nedyalkov, A. E. Shadrichev, V. G. Shtengel

Introduction. The cavities that have been formed under fastening plates of channels ground slopes represent a danger to reliable operation of hydraulic structures. Now there is no accessible technique for detection of such cavities.
Method. We have developed and offered a comprehensive instrumental technique for solving this problem; the technique includes successive application of thermovisional and ground penetrating radar (GPR) methods of NDT.
At the first stage the full area of fastening plates are scanned with a thermovision method for detecting of zones where cavities are possible. At the second stage the detected potentially dangerous zones are examined with a GPR method for cavities confirmation and sizing.
Simplicity and accessibility of the technique seem to be easy in use but this is misleading. Correct application of the technique should take into account the boundary conditions that include: background and mask external actions on the obtained information; structure features of the reinforced concrete plates, both fastening and base; plates’ surface condition; inspection conditions; specifics of each stage results handling and analysis.
Results. Application of the abovementioned NDT methods combination within the recommended boundaries makes it possible to obtain the reliable information. The results of physical and mathematical simulation as well as experimental field testing are given.
Conclusion. The technique with consideration of the stated boundary conditions is applicable for examination of a wide range of similar structures.
 
Keywords: hydraulic structure, reliability, comprehensive instrumental technique, features of application, heat monitoring, comparative thermography, thermogram, GRP inspection, powergram, antenna, kern, recognaissance operations, mathematical and physical simulation, field observation, concrete structures
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