Geophysical Evaluation of the Inner Structure of a Historical Earth-Filled Dam

Abstract

Small earth dams usually lack the detailed seepage monitoring system that would provide high resolution data on changes in seepage flow. Alternative solution is monitoring of the temperature and electrical resistivity in the body of the dams. Geophysical methods are useful techniques for a non-destructive exploration of the subsurface. We have utilized the combination of electrical resistivity tomography (ERT), ground penetrating radar (GPR) and multi-depth electromagnetical conductivity meter (CMD) techniques to observe the inner structure, especially internal failures, of the historical earth-filled dams. Longitudinal and transversal profiles of four typical fishpond dams in the Czech Republic were measured within this research. The dams were constructed as early as in the 15th century, some of them went through minor reconstruction. The aim of the application of geophysical methods for investigation of old fishpond dams was to detect and localize the boundary of the dam foundation, new earth material from the reconstruction works, cone of water depression, technical objects location, potential internal erosion, cavities, inhomogeneity in the water content pattern and any other anomalies. The primary results show that the ERT is suitable to observe the dam stratification, dam foundation, bedrock below the dam and large anomalies. GPR is suitable for small objects and anomalies detection in the shallow depths.

The earth-fill dam state express investigation using mechanical vibrations produced by HPP

“…Surface erosion may lead to loss of dam stability. In general, dams are systematically surveyed on the basis of geodetic, geotechnical and seismic methods, for example [9][10][11][12][13]. Some authors use GNSS techniques [14,15], interferometric synthetic aperture radar (InSAR) methods [16][17][18][19], spirit leveling [20,21] and motorized control total stations systems [9,22].…”

Geophysical survey of earthen dam using the electrical prospecting methods

“…The world experience shows that the geophysical methods of non-destructive testing are widely used to determine the safety of hydraulic structures. The applied geophysical methods are sufficiently described in works (Camarero and Moreira, 2017;Dzhurik et al, 2014;Fatoba et al, 2018;Kayode et al, 2018;Kolesnikov et al, 2009;Kolesnikov et al, 2012;Nwokebuihe et al, 2017;Olasunkanmi et al, 2018;Prigara et al, 2012;Prigara et al, 2014;Zumr et al, 2018). An analysis of these works indicates that the seismic methods, georadar sounding and various modifications of electrometric methods are widely used.…”