報告書番号

U86037

タイトル（和文）

第四紀地盤上の高速実験炉「常陽」の地震応答特性（その３）地震観測に基づく地盤～建屋の応答特性と根入れ効果の簡易予測手法

タイトル（英文）

EARTHQUAKE RESPONSE CHARACTERISTICS OF LARGESTRUCTURE JOYO DEEPLY EMBEDDED IN QUATERNARY GROUND (PART 3) DYNAMICCHARACTERISTICS BASED ON EARTHQUAKE OBSERVATION AND EVA

概要 （図表や脚注は「報告書全文」に掲載しております）

第四紀地盤上に深く根入れされた高速実験炉「常陽」の地震観測結果をとりまとめ，地盤～建屋の応答特性および根入れ効果を簡易に予測するために必要なモデル化，入力地振動の取り扱いについて検討した。１）増幅率は，地表では基盤に対して２～４倍であるが，建屋項部では１倍強で著しい根入れ効果が確認された。２）各測点間より得た伝達関数によると，卓越周波数は起振実験結果と良く一致することが確認された。また，地表～建屋基礎と地表～基礎同深度の地中とを比較すると，その特性は互いに良く近似し，基礎の地震時挙動は第一近似的には同深度の地中の挙動より推定できることを示唆する。３）Ｓ－Ｒモデルの応答値は基礎同深度の地中波形を入力とした場合が振幅値，スペクトルとも観測値に最も良く近似し，側方バネを厳密に評価しない簡易モデルを採用した場合でも，ほぼ実際に近い応答を評価できるものと考えられる。

概要 （英文）

IN ORDER TO EXAMINE ASEISMICITY OF EMBEDDED STRUCTURE AND TO CLARIFY EMBEDMEUT EFFECT,EARTHQUAKE OBSERVATIONS OF THE LARGE STRUCTURE JOYO WERE CARRIED OUT,WHICH IS DEEPLY EMBEDDED IN QUATERNARY GROUND. IN THIS REPORT,EARTHQUAKE OBSERVATION RESULTS ARE SUMMERIZED AND USEFUL METHOD TO ASSESS EMBEDMENT EFFECT BY USING S-R MODELIS PROPOSED FROM A COMPARISON OF CALCULATION WITH OBSERVATION. THE RESULTS ARE SUMMERIZED AS FOLLOWS. (1)THE AMPLIFICATION FACTORS OF MAXIMUMAMPLITUDE ARE 3 TO 4 TIMES BETWEEN BEDROCK AND GROUND SURFACE. ON THE CONTRARY,NO AMPLIFICATION IS OBSERVED IN UNDERGROUND PORTION OF THE STRUCTURE,AND ONLY A LITTLE AMPLIFICATION EXISTS IN THE ABOVE-GROUND PORTION OF THE STRUCTURE. (2)TRANSFER FUNCTION BETWEEN BEDROCK AND GROUND SURFACE HAS SEVERAL PREDOMINANT PEAKS AT THE FREQUENCIES OF 1HZ,2.5HZ,4HZ,AND IN THE RESPONSE OF STRUCTURE,SPECTRAL PEAKS EXIST AT FREQUENCIES 4.3HZ AND 8.0HZ,WHICH WELL COINCIDE WITH VALUES OBTAINED FROM FORCED VIBRATION TESTS. IT IS SHOWN THAT TRANSFER FUNCTION BETWEEN BASEMENET AND GROUND SURFACE IS SIMILAR TO THAT BETWEEN GROUND AT THE SAME LEVEL TO BASEMENT AND GROUND SURFACE,SUGGESTING THE BEHAIVOIR OF BASEMENT TO BE ABLE TO ESTIMATE BY THESE UNDERGROUND EARTHQUAKE MOTION. (3)AS A RESULT OF EARTHQUAKE MOTION ANALYSIS OF STRUCTURE BY USING S-R MODELS,ONE OF WHITH CONSIDERED ONLY THE BASE GROUND STIFFNESS AND ANOTHER CONSIDERED THE STIFFNESS OF THE SIDE GROUND AT EMBEDMENT PORTION ESTIMATED FROM FORCED VIBRATION TESTS BESIDES,THE FOLLOWING IS CLARIFIED. 1)WHETHER OR NOTHE SIDE GROUND STIFFNESS IS CONSIDERED,THE CALCULATED RESPONSE VALUESDO NOT DIFFER SO MUCH. 2)THE CALCULATED CORRESPOND WITH OBSERVATION DATA WHEN THE UNDERGROUND EARTHQUAKE MOTION AT THE SAME LEVEL TO BASEMENTIS USED AS A INPUT WAVE.

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