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[VI-104] Countermeasures for bank displacement in large-scale cutting of existing dams

〇Yuichiro Ogawa¹, Satoshi Suzuki¹, Hiroki Kirishima¹, Fujita Hiroshi², Eisuke Amano², Hitoshi Yoshida³ (1.KAJIMA CORPORATION, 2.Ministry of Land, Infrastructure, Transport and Tourism, 3.Japan Dam Engineering Center)

Keywords:dam, renewal, Structure removal, Behavior observation, Spillway cutting

At the Nagayasuguchi Dam, the dam is being cut and demolished while the dam is in service, and the dam is being remodeled by adding two new spillway gates. As a result of observing the behavior of the embankment at the time of construction of BL.9,10, which is the first cutting point, the displacement (opening) of the embankment transverse joint J10, which could not be predicted at first, was observed. At BL.11 and 12, the second place, there was a concern that the displacement would further progress, so we decided to take measures against displacement. On the other hand, embankment cutting is a critical path for this work, and no delay in the process due to the implementation of countermeasures was allowed.