地盤の3次元応力~浸透連成解析システムの開発
地盤の土粒子骨格と間隙流体の連成作用を地盤の非線形性も考慮した上で3次元的に解析し得る解析システムの開発を行い、その有効性について検討を行った。開発に際しては、Biotの3次元圧密方程式を基に、変位および間隙水圧の両方を節点値で離散化する連成解析手法を用いて、有限要素定式化を行った。
線形弾性体の1次元圧密問題を取り上げ、本システムによる解析値とTerzaghiの理論解との比較を行った結果、解析値は理論値とよく一致しており、本システムの妥当性が確認できた。また、矩形盛土問題について、3次元圧密解析を行い、2次元解析との比較を行った結果、2次元解析では盛土中心部の沈下量を過小に、また、盛土端部の沈下量および法尻部の側方変位を過大に評価してしまうことがわかり、このような問題に対する3次元解析の必要性が確認できた。
Three Dimensional Coupled Stress-flow Analysis System for Geotechnical Problems
An analysis system by which three dimensional geotechnical problems can be analyzed taking account of the coupling action between the soil skeleton and pore water is developed and its validity is investigated. This system is based on Biot's three dimensional consolidation theory and formulized in finite element equations by means of a coupled analysis method.
A one dimensional consolidation problem of a linear elastic body is analyzed by this system. From the results of a comparison between the analytical values and Terzaghi's theoretical values, the analytical values agree with the theoretical ones very well and so it is proved that this system is useful. Further, a three dimensional consolidation analysis of a rectangle embankment is performed and compared with a two dimensional analysis. Consequently, it is proved that the two dimensional analysis underestimates settlement at the center of the embankment, and overestimates settlement at the edge of the embankment and a lateral displacement at the end of the embankment slope. Accordingly, it is necessary to apply this three dimensional analysis for such problems.