三城目安山岩のせん断強度の載荷速度依存性

1.はじめに

2.試料岩石および実験方法

3.変形特性

 (1) せん断応力−せん断変位曲線

 (2) 垂直変位−せん断変位曲線

4.せん断強度と残留強度

 (1) 載荷速度依存性

 (2) 垂直応力依存性

 (3) 粘着力の載荷速度依存性

5.考察

6.まとめおよび今後の課題

参考文献


LOADING-RATE DEPENDENCY OF SHEAR STRENGTH OF SANJOME ANDESITE

In this study, direct shearing tests of Sanjome andesite were carried out under three shear displacement rates (5×10−5,5×10−4,5×10−3 mm/s) and four normal stresses (10, 20, 30, 40 MPa) by a servo-controlled testing machine. When shear displacement rate was increased by a factor of 10, increment of shear strength was about 1.2MPa. Relative increment against shear strength was about 6 % that almost coincides with the values obtained in uniaxial tension and compression tests. It can be said that loading rate dependency of shear strength is similar to those of uniaxial tensile and compressive strength. The relationship between failure criteria and loading rate dependency was also discussed.

Key Words : loading rate dependency, direct shearing test, shear strength, time dependency, failure criteria, cohesion


本研究ではサーボコントロ−ル式試験機を用い,3種類の定載荷速度(5×10−5,5×10−4,5×10−3 mm/s)と4種類の垂直応力(10,20,30,40 MPa)で一面せん断試験を行い,三城目安山岩のせん断強度の載荷速度依存性を調べた.その結果,載荷速度を1桁増加させると,せん断強度(粘着力)は1.2MPa増加することがわかった.増加率は約6%であり,これは載荷速度を1桁増した時の一軸圧縮強度および引張強度の増加率とほぼ同じである.この結果を踏まえ,破壊条件と強度の載荷速度依存性についても検討した.

キーワード:載荷速度依存性,直接せん断試験,せん断強度,時間依存性,破壊条件,粘着力