報告書番号

N08005

タイトル（和文）

原子力発電所建屋近傍埋戻し地盤の沈下メカニズムの解明（その1）－1G場模型振動台実験による検討－

タイトル（英文）

Settlement mechanism of the backfilled ground around nuclear power plant buildings (Part I) - A series of 1G shaking table tests -

概要 （図表や脚注は「報告書全文」に掲載しております）

2007年新潟県中越沖地震により，東京電力柏崎刈羽原子力発電所敷地内では，原子力発電所建屋近傍の埋戻し地盤で局所的に大きな沈下が発生した．本研究の目的は，剛な構造物と砂地盤を用いた1G場模型振動台実験により，原子力発電所建屋近傍地盤で生じた沈下現象のメカニズムを解明し，その沈下量に影響を与える因子を明らかにすることである．地盤－構造物間の相対水平変位や，すべりに抵抗する地盤強度特性に関するパラメータを変化させた一連の実験より，以下の知見を得た．
(1)実施した全ての実験ケースにおいて，構造物近傍地盤の沈下量は構造物から離れた地盤の沈下量よりも大きかった．
(2)構造物近傍地盤の画像計測より，地盤が構造物から離れた後に，すべり破壊により局所的な沈下が発生したことが分かった．
(3)地盤－構造物間の相対水平変位が大きいほうが構造物近傍地盤の沈下量は大きかった．また，細粒分を加えたことによる地盤強度の増大は，構造物近傍地盤の沈下量の大きさに影響を及ぼした．

概要 （英文）

The large ground settlement locally occurred at the backfilled ground around the Kashiwazaki-Kariwa Nuclear Power Plant buildings during the Niigataken Chuetsu-oki Earthquake in 2007. The purposes of this study are to verify the assumed mechanism of the settlement and to discuss the influence factors on the settlement. For these purposes, we conducted a series of 1G shaking table tests using a rigid structure and sand. In the tests, parameters, which were variously changed, are related to two factors; one is the horizontal ground displacement relative to the structure, the other is the ground strength against the sliding failure. The following results were obtained:
(1) All the results showed that the ground settlement sizes near the structure were larger than the ground settlement sizes far from the structure,
(2) From the video observed at the ground near the structure, it was found that the settlement locally occurred due to the sliding failure after the ground was separated from the structure,
(3) The ground settlement sizes near the structure were large as the horizontal ground displacement sizes were large, and the soil strength arising from fines affected the ground settlement sizes near the structure.

報告者

キーワード