IDENTIFICATION OF AREAS OF WATER FILTRATION FROM RESERVOIRS

Detection of zones of increased water content in the body of dams by GPR

Filtration of water from reservoirs under the action of increased static pressure of water masses is normal process and in stationary mode and the presence of drainage channels does not threaten the safety of dams. The danger of dam destruction in high floods occurs in places of high filtration speed and the encouragement of bulk soils..

Distribution of palaeokarst in the river valleys , cutting through the bedrock of sulfate-carbonate composition, and accelerated the karst processes along the shores of artificial reservoirs contribute to the emergence of channels of water filtration through the dam and foundations of dams. The accelertaion of filtration processes captures bulk soils of protective dams, which increases the likelihood of erosion and destruction in the event of extreme floods.
On the GPR sections the zone of increased saturation and filtration in the dam body and foundation are displayed by increased amplitudes of reflected signals

Refracted wave seismic method of detection of possible filtration zones

Seismic methods of detection and localization of filtration channels are usually used in cases where it is necessary to assess the depth of their penetration into the thickness of the rocks at the foundation of the dam, since the depth of the GPR method is often limited by the surface of full water saturation.
The method of refracted waves allows to characterize in detail the structure of the weathered surface of halogen-carbonate rocks and to determine the areas of evolution of palaeocarst cavities to which the channels of water filtration from the reservoir are usually confined.

Reflected wave seismic method of possible filtration zones detection

Seismic method of reflected waves in modification of SDP (Gommon depth point) with multiple accumulation of signals reflected from one section of the boundary, allows to map not only the surface of the bedrocks, but also reflecting boundaries in their thickness.
The CDP method is more time-consuming and expensive compared to the method of refracted waves, requires more complex data processing. But at the same time it allows to identify the manifestations of palaeokarst and, accordingly, potential channels of filtration at considerably greater depths up to several tens of meters.