報告書番号

382039

タイトル（和文）

地下式原子力発電所空洞の耐震性の検討－その２．２次元震動応答解析法による空洞の地震時安定性の検討－

タイトル（英文）

EARTHQUAKE RESISTANCE OF CAVERN FOR UNDERGROUND NUCLEAR POWER PLANTS (2) -STUDY ON THE STABILITY OF THE UNDERGROUNDCAVERN DURING EARTHQUAKE USING TWO-DIMENSIONAL SEISMIC RESPOSE ANALYSIS-

概要 （図表や脚注は「報告書全文」に掲載しております）

我が国において，地下式原子力発電所の立地条件に適した海岸山腹に分布する岩盤物性を想定し，空洞上部の土被り厚さが１００ｍ，幅３２ｍ，高さ４６ｍ，奥行き長さ７０ｍのトンネル型の原子炉空洞をモデルにして，水平地震動４０７ｇａｌおよび鉛直地震動２０４ｇａｌが作用した時に空洞近傍の岩盤に発生する地震力による応力を動的解析から求めた。そして，この応力に常時応力を重ね合せた合応力が，岩盤の破壊包絡線にどの程度接近しているかで空洞の安定性を判定した。その結果，地震時緩み領域（合応力が破壊包絡線を切った領域）は，水平地震動が作用する場合も鉛直地震動の場合も，空洞天端付近にわずかに発生する程度で，アーチコンクリート内面からのその深さは高々１０ｍであることがわかった。この緩み領域は，現在の補強技術をもってすれば，ロックアンカーやアーチコンクリートで十分に対処可能と思われる。

概要 （英文）

UNDERGROUND NUCLEAR POWER PLANTS HAVE BEEN STUDIED AS ONE OF NEW SITING FORMS OF THE NUCLEAR POWER PLANTS. THIS FORM IS THAT SOME OR ALL OF NUCLEAR POWER PLANT SWOULD BE CONTAINED IN THECAVERNS WITHIN THE ROCK MASS. LARGE UNDERGROUND CAVERNS SUCH AS THE REACTOR VESSEL CAVERN SHOULD BE EXCAVATED AT THE CONSTRUCTION. THEREFORE,THE STUDY ON THE STABILITY OF SUCH LARGE UNDERGROUND CAVERNS CONTAINING BIG IMPORTANT STRUCTURE WILL BE VERY IMPORTANT IN CASE OF THE DESIGN OF THE UNDERGROUND POWER PLANTS. THE CHARACTERISITICS OF THE ROCK MASS SITUATED IN THE COASTAL HILLSIDE SUITABLE TO THE SITING CONDITIONS OF THE UNDERGROUND NUCLEAR POWER PLANTS IN JAPAN WERE ESTIMATED. THE STABILITY DURING EARTHQUAKE OF THE REACTOR VESSEL CAVERNS OF THE TUNNEL TYPE WITH THE WIDE OF 32M, THE HEIGH OF 46M, AND THE LENGTH OF 70M ABOVE WHICH THE THICKNESS OF EARTH COVERING IS 100M WERE ANALYZED. THE DYNAMIC STRESSES AT THE SURROUNDING ROCK MASS OF THE CAVERNS UNDER THE HORIZONTAL EARTHQUAKE WITH 407 GAL AND THE VERTICAL EARTHQUAKE WITH 204 GAL WERECALCULATED. IT WAS OBTAIN FROM THE RESULTS THAT THE RELAXED ZONE DURING EARTHQUAKE WAS YIELDED JUST AT THE ABUTMENT OF THE UNDERGROUND IN CASE OF BOTH THE HORIZONTAL EARTHQUAKE AND THE VERTICAL EARTHQUAKE, AND THE DEPTH OF THE RELAXED ZONE WAS 10M AT ALMOST FROM THE ARCH CONCRETE. IT IS SEEMED THAT SUCH RELAXED ZONE CAN BE TREATED WITH ROCK ANCHORS ANDARCH CONCRETES CONSIDERING THE CURRENT REINFORCEMENT TECHNIQUE.

報告者

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