報告書番号

U87029

タイトル（和文）

地震時における基礎地盤の安定性評価（その４）－土粒子の骨格と間隙水の相互作用を考慮した応答解析法の開発－

タイトル（英文）

EVALUATION OF STABILITY OF FOUNDATION GROUNDDURING EARTHQUAKES (PART4)-DEVELOPMENT OF RESPONSE ANALYSIS WITH SOIL SKELETON-PORE WATER INTERACTION-

概要 （図表や脚注は「報告書全文」に掲載しております）

第四紀地盤を対象とした原子力発電所の耐震性は，地盤の地震時安定性に強く依存している。地盤の地震時挙動は，地盤内の間隙水圧と密接な関係があるため，地盤の安定性評価を詳細に行うためには間隙水圧の変動を追跡できる有効応力解析を行う必要がある。本報告は，地盤を土の骨格と間隙水に分け，その相互作用を考慮したビオの理論に基づく厳密な有効応力解析を有限要素法を用いて行うためのプログラム開発と線形範囲でその適用を行った結果について述べたものである。その結果，現実的な透水係数を対象とした動的解析では，集中質点糸を用いて解析を行っても間隙水圧に誤差がほとんど生じないこと，地盤－構造物系の解析を行ったところ，構造物の最大応答加速度は透水係数に依存し，透水係数が大きいほど最大加速度が小さくなること等がわかった。

概要 （英文）

THE ASEISMICITY OF NUCLEAR POWER PLANTS SITED ON THE QUARTERNARY GROUND WHICH CONSISTS OF SAND AND GRAVEL IS DEPENDENT ON THE STABILITY OF THE GROUND DURING EARTHQUAKES. AS IS COMMONLY KNOWN,THE BEHAVIORS OF GROUND DURING EARTHQUAKES ARE CLOSELY RELATED WITH THE PORE WATER PRESSURE,TO EVALUATE THE STABILITY OF GROUND IN DETAIL,IT IS NECCESSARY TO DO THE EFFECTIVE STRESS ANALYSIS WHICH PURSUITS THE CHANGE OF PORE WATER PRESSURE. IN THIS REPORT WE DESCRIBE THE RESUITSOF DEVELOPMENT ABOUT DYNAMIC EFFECTIVE STRESS ANALYSIS METHOD BASED ONTHE BIOT,S THEORY CONSIDERING THE SOIL AND PORE WATER INTERACTION AND ITS APPLICATION. THROUGH THIS STUDY,THE FOLLOWINGS ARE OFTAINED. (1)THIS METHOD IS TAKEN INTO ACCOUNT THE INTERACTION BETWEEN SOIL SKELETON AND PORE WATER. THEREFORE,WE CAN DO THE EFFECTIVE STRESS ANALYSIS BY WHICH DIRECTLY AND ESSENTIALLY CALCURATE THE CHANGES OF PORE WATER PRESSURERESPONDED TO THE GROUND DEFORMATION.(2)BY USING THIS METHOD,WE ANALYZETHE DELTA ONE DIMENSIONAL CONSOLIDATION AND BASIC DYNAMIC PROBLEMS. AND CONFIRM THAT THE RESULTS OF THIS ANALYSIS ARE IN GOOD AGREEMENT WITH THE EXACT SOLUTIONS.(3)APPLYING THIS METHOD TO THE TWO-DIMENSIONAL EARTHQUAKE RESPONSE ANALYSIS ON THE ASSUMPTION THAT THE GROUND IS CONSISTEDOF ELASTIC SATURATED POROUS MEDIA,IT IS KNOWN THAT WE CAN CALCURATE THE TWO-DIMENSIONAL DISTRIBUTION OF PORE WATER PRESSURE DEPENDENT ON THE GROUND PERMEABILITY COINCIDED WITH THE GROUND DEFORMATION,AND THE LARGER THE GROUND PERMEABILITY BECOME,THE SMALLER THE MAXIMUM RESPONSE ACCELERATION OF STRUCTURE IS.

報告者

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