LONG-TERM BEHAVIOR OF KUROBE DAM AND ITS FOUNDATION ROCK

摘要

Kurobe Dam, operated by Kansai Electric Power Co., Inc. (KEPCO), has been monitored for about 40 years since the first reservoir filling in 1960, mainly through the measurements taken for the dam body itself, as well as for the foundation rock. The long-term measurements revealed the following two points: First, highly accurate measurements on the valley width near the dam and detailed analyses on the data clearly revealed seasonal fluctuation in the width. By taking into consideration this "mountain deformation" phenomenon, rational explanation was made possible for actual deflection measurements at the dam crown, which could not be properly evaluated based only on hydrostatic pressure of the reservoir and thermal load. Second, detailed analyses on long-term measurements by rock deformeters revealed the continuous deformation in some part of the rock after the first full water, though it is infinitesimal in scale. These two phenomena were clarified only through the long-term measurements conducted at the dam, and the authors believe such data are rare and unique, not seen in the studies by overseas researchers.