一軸圧縮荷重下での岩石のクリープ特性

1.はじめに

2.実験装置と試料岩石

 2.1 実験装置及び実験方法

 2.2 試料

3.クリープ実験結果

 3.1 一次クリープ領域における歪、歪速度の経時変化

 3.2 三次クリープ領域における歪、歪速度の経時変化

 3.3 クリープ歪と歪速度の関係

 3.4 各岩石における特徴

4.考察とまとめ

参考文献

キーワード: 岩石,一軸圧縮,クリープ,残存寿命,応力−歪曲線


Creep Behavior of Rock under Uniaxial Compression

Abstract

Uniaxial conpression creep tests were conducted under comparatively high stress level (90-95% of strength) on Inada-granite, Tako-sandstone, cement-mortar and Akiyoshi-marble. the following results are obtained;

1) In all samples, the primary creep follows the logarithmic creep law.

2) The secondary creep where strain rate is nearly constant is apparent only for cement-mortar. For other samples, the strain rate continuously decreases at first, and increases after taking its minimum.

3) For Tako-sandtone and Akiyoshi-marble, the value of creep strain at minimum strain rate is nearly equal to half of the width of the complete-stress-strain curve cross-sectioned at corresponding creep stress. In case of granite, the creep strain at minimum strain rate is rather small, whereas, in case of cement-mortar nearly double of the width.

4) Strain rate at an arbitrary time in tertiary creep is inversely proportional to the residual time up to final failure. If this law is applied to rock mass, the failure of underground constructions may be predicted.

5) Except cement-mortar, the creep strain just before final failure (1 sec before failure) is nearly equal to the cross-sectional width of the complete-stress-strain curve. In case of cement-mortar, the creep strain just before funal failure is as much larger than the width.

Key Word: Rock, Uniaxial compression, Creep, Residual time, Complete-stress-strain curve