Numerical Simulation of Active Heat Injection and Anomalous Seepage near an Earth Dam–Concrete Interface

Abstract

Active heat injection and temperature monitoring are methods that may have potential for the detection of anomalous seepage at the interface between earth dams and concrete structures. A finite-element modeling investigation was conducted to assess the feasibility of using such a seepage-detection approach. Anomalous seepage at the interface between a clay and concrete structure was simulated by increasing the hydraulic conductivity in a 3-m-thick zone and imposing a range of hydraulic gradients. The results indicate that the heat-injection location would need to be less than 1.0 m from the interface to ensure seepage-related temperature deviations of 1.0°C or greater. Provided the heat-injection location is within 1.0 m of the interface, it is concluded that the interpretation of temperature data collected prior to, during, and following heat injection should be a feasible method for identifying locations of anomalous seepage. A simulation with realistic dam geometry, including seasonally varying reservoir and air-temperature boundary conditions, showed that these factors should not overwhelm the temperature deviations generated by active heating.