Changes of a Geocryologic Condition of Earthfill Dams in Western Yakutia and Optimization of Monitoring by a Complex of Geophysical Electroprospecting Methods

Abstract

Based on field observations, this study proposes ways to improve the efficiency of permafrost monitoring in earthfill dams by using the optimal combination of geophysical methods. It discusses the main environmental factors controlling dam embankment temperatures. It is found that the most important factors are mean annual and minimum near-surface air temperatures and cold period length. The capabilities of geophysical methods for dam thermal monitoring in Western Yakutia are considered. Some approaches are proposed on how to optimize the use of several geophysical methods in application to the existing conditions. The optimal combination of DC and AC electrical resistivity applied with RMT sounding year round is presented as an example. The VES and VES-FR methods used with ERT procedures provide profiles of apparent resistivity and dielectric permittivity module in the earthfill. The use of RMT in complex with electrical techniques will provide better 2-D and 3-D representation of the location and development of thaw and water-bearing zones in the dams.