Failure Criterion and Long-Term Strength of Rock

岩石的破坏准则和长期强度

• 批准号: 11450395
• 负责人: OKUBO Seisuke
• 金额: $ 5.12万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11450395/
• 关键词: Rock; Failure Criterion; Long-Term Strength; Underground Structures; Rock Stress; Creep; Relaxation; Constitutive Equation; 粘弾性; 時間依存性; 緩み領域; 圧密

At first, study on loading-rate dependency of strength was briefly summarized. It is well known that uniaxial (unconfined) compression strength increases with loading rate. Though only limited data are available, some authors reported that confined strength increases with loading rate. Also, tensile strength obtained by uniaxial tension, indirect tension and bending tests increases with loading rate.Based on the summarized experimental results, a failure criterion in which loading-rate dependency of strength is considered was proposed ; high criterion for high loading rate and low criterion for low loading rate. As an extreme case, long-term strength or failure criterion at extremely low loading rate can be obtained. The simplest form of the long-term strength is σ_1=a σ_3 where σ_1, σ_3 are major and minor principal stresses, and constant 'a' varies from 2 to 6 depending on rock.For validation of the proposed failure criterion, rock stresses were plotted on σ_1 vs. σ_3, diagram. It was found that all data except one were plotted under the line σ_1=4_<3σ>. It is reasonable to consider that, in relatively stable rock mass, rock stress is maintained at a certain value or condition lower than a long-term strength. If so, this result supports the validity of the proposed failure criterion.

首先，对强度的加载速率相关性研究进行了简要的综述。众所周知，单轴（无侧限）抗压强度随加载速率的增加而增加。虽然只有有限的数据，一些作者报道，侧限强度增加加载速率。在此基础上，提出了一个考虑加载速率相关性的强度失效准则，即高速率时的强度失效准则和低速率时的强度失效准则。作为一种极端情况，可以在极低的加载速率下获得长期强度或破坏准则。长期强度的最简单形式为σ_1=a σ_3，其中σ_1、σ_3分别为主应力和次主应力，常数“a”随岩石的不同而在2 ~ 6之间变化。发现除一个数据外，所有数据都在σ_1=4_<3σ>线下作图。可以合理地认为，在相对稳定的岩体中，岩石应力保持在低于长期强度的一定值或条件下。如果是这样的话，这个结果支持建议的失效准则的有效性。

项目成果

大久保誠介: "緩み領域の強度回復に関する一考察"資源・素材 1999(京都)講演論文集. A1. 9-10 (1999)

Seisuke Okubo：“松散区域强度恢复的研究”资源和材料 1999 年（京都）讲座记录 A1。

OKUBO,Seisuke: "A Consideration on healing of fractured zone around tunnel."J.MMIJ, Proc.Fall Meet.. (A1). 9 (1999)

OKUBO，Seisuke：“关于隧道周围断裂带愈合的考虑。”J.MMIJ，Proc.Fall Meet..（A1）。

杉田隆博: "破砕した岩石の強度回復"資源・素材2000(秋田)講演論文集. A. 135-136 (2000)

Takahiro Sugita：“碎石强度的恢复”Resources and Materials 2000（秋田）讲座论文集 A. 135-136 (2000)。

杉田隆博: "破砕した岩石の強度回復"資源・素材 2000(秋田)講演論文集. A. 135-136 (2000)

Takahiro Sugita：“碎石强度的恢复”Resources and Materials 2000（秋田）讲座论文集。

大久保誠介: "緩み領域の強度回復に関する一考察"資源・素材1999(京都)講演論文集. A1. 9-10 (1999)

Seisuke Okubo：“松散地区强度恢复的研究”资源和材料学报 1999 年（京都）9-10（1999 年）。