开挖与支护应力路径下硬岩破坏过程的真三轴与声发射试验研究

针对硬岩的脆性破坏问题，利用真三轴和声发射（AE）试验系统研究了灰岩试样在不同应力路径和应力水平下的力学特征与变形破坏机理、AE活动特征及能量释放规律。试验研究表明：（1）开挖卸荷应力路径下，试样强度受卸荷作用影响较大，且随中间主应力呈区间性变化，试样以脆性劈裂破坏为主；（2）开挖卸荷+支护的应力路径下，支护力显著改善了岩石的力学性质，破坏形式以张剪性破坏为主；（3）试样AE活动过程可以分为三个活跃期（裂隙压密阶段、卸荷阶段和失稳-破坏阶段）和两个相对平静期（弹性变形阶段和微破裂稳定发展阶段），AE信号表征参数“absolute energy”作为能量度量指标能够较好地定量描述和研究硬岩的脆性破坏过程。试验结果和许多工程开挖和支护过程中岩体的力学行为和支护作用类似，可为工程现场开挖支护设计提供试验依据和有益指导。

True triaxial and acoustic emission experimental study of failure process of hard rock under excavating and supporting stress paths

Aiming at brittle failure of hard rock(taking limestone for example),true triaxial and acoustic emission experiments are adopted to study the mechanical characteristics,deformation and failure mechanisms,characteristics of acoustic emission(AE) activities and law of energy release.The experimental results indicate:(1)Under the unloading stress path,strength of specimens is apparently effected by unloading,and varies in intervals along with the intermediate principal stress.Failure modes of most specimens ar...