コンプライアンス可変型構成方程式の拡張とクリープ試験結果による検討

1.はじめに

2.構成方程式の拡張

3.大久保・西松(1986)がおこなった一軸圧縮応力下でのクリープ試験結果による検討

 3・1 応力レベル77%の歪速度曲線からのパラメータの導出

 3・2 応力レベル77%のクリープ試験結果と数値計算結果との比較

 3・3 応力レベル87%のクリープ試験結果

4.福井ら(1992,1993)がおこなった一軸圧縮応力下でのクリープ試験結果による検討

 4・1 応力レベルを変えたクリープ試験結果

 4・2 強度破壊点以降でのクリープ試験結果

5.秋ら(1995)がおこなった一軸引張応力下でのクリープ試験結果による検討

6.構成方程式中のパラメータについて

7.考察

 7・1 一軸圧縮試験への拡張の可能性

 7・2 周圧下への拡張の可能性

 7・3 FEMなどへの組み込みの可能性

 7・4 他の構成方程式との関係

8.まとめ

キーワード:岩石,安山岩,クリープ,粘弾性, 時間依存性,構成方程式


Extension of Constitutive Equation of Variable Compliance Type and its Validation based on Creep Data

A constitutive equation of variable compliance type had been proposed by Okubo in 1987. The equation is simple and its parameters are relatively easy to obtain. The equation can be applicable to creep of rock, however, experimental result in primary creep region in which strain rate is decreasing with time does not conform well to the calculated result.

Recently Okubo & Fukui (2002) proposed a constitutive equation especially focusing on low stress level creep. In this study, old one proposed in 1987 and new one proposed in 2002 are combined to extend an applicable range of the constitutive equation of variable compliance type.

For validation of the proposed constitutive equation, calculated results are compared with the experimental data by Okubo & Nishimatsu (1986) and Fukui et al. (1992, 1993), and it can be said that experimental results in uniaxial compression can be well simulated by the proposed equation. The equation is also tested against the creep performed in uniaxial tension and possible applicability of the equation to tensile stress field is discussed.

Key Words: Rock, Andesite, Creep, Visco-Elasticity, Time dependency, Constitutive Equation