Evaluation of Thermal Conductivity and Deformation Properties of Mass Concrete Based on Measurement Data of a Hightened Concrete Gravity Dam

Abstract

This study analyzed the thermal behavior of a concrete gravity dam to support planning of thermal-stress countermeasures for dam heightening. Temperature, strain, and stress were measured in the existing and newly placed dam bodies over five years, from the start to the completion of heightening work. The measurements clarified the spatial distribution and temporal variation of temperature in the dam concrete. Based on these data, a temperature prediction equation was developed for the period from immediately after placement to thermal stabilization, using ambient temperature, depth, and elapsed time as parameters. Although discrepancies between predicted and measured temperatures were observed in the early stage after placement, the equation provided generally good accuracy during the stabilization stage. The coefficient of thermal expansion and elastic modulus of the dam concrete were also evaluated from the measured data. In addition, an analysis was performed to reproduce the dam deformation observed during trial impoundment after completion of the heightening work. The results indicated that the evaluated material properties, measured data, and analytical conditions were generally reasonable.