GEOPHYSICAL MODEL OF THE HYDROGEOGENIC ICING SOURCE IN THE CHUYA BASIN (GORNY ALTAI)
V.V. Olenchenko, A.A. Zaplavnova, M.V. Medvedeva
Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: icing, permafrost, groundwater filtration, ground penetrating radar, electrical resistivity tomography, normalized chargeability
Abstract
Icing formation represents a hazardous engineering-geological process that adversely affects infrastructure facilities. To predict icing development and suggest adequate control measures, it is necessary to identify the location of the icing water source and plan the placement of water intake wells. Geophysical methods help solve these tasks. The objective of this study was to investigate the structure of the groundwater discharge zone feeding a hydrogeogenic icing to plan anti-icing measures. The investigations employed ground-penetrating radar (GPR) equipped with an OKO-3 system and a 250 MHz antenna, capacitive-coupled resistivity measurements using VEGA instrument at 16.5 kHz frequency, and electrical resistivity tomography with induced polarization measurements using Skala-64k15 system. GPR data revealed that the seasonal freezing depth within the icing mound reaches 1.8-2.7 m. Signs of groundwater discharge were identified as local anomalies with reduced seasonal freezing depth down to 1.3 m. The study established that the icing mound forms over a seasonal frost heave mound containing an ice core, while the bedrock base shows evidence of a fault zone. Electrical resistivity tomography surveys and 3D modeling of resistivity and normalized chargeability distributions to a depth of 100 m enabled the identification and delineation of branching vertical channels of ascending groundwater filtration. These channels form a group source feeding the icing.
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