Analysis of the crack propagation rules and regional damage characteristics of rock specimens
Analysis of the crack propagation rules and regional damage characteristics of rock specimens
复制标题
岩石试件裂纹扩展规律及区域损伤特征分析
DOI：
10.12989/gae.2021.24.3.215
复制
发表时间：
2021-02-10
影响因子：
3.2
通讯作者：
Fu, Guangsheng
中科院分区：
文献类型：
--
作者：
Li, Yangyang;Xu, Yadong;Fu, Guangsheng
为研究多缺陷岩石中裂纹的演化机理，采用含多缺陷岩石试样，如条形贯通裂纹和孔洞群，研究了不同倾角下裂纹扩展规律及孔洞群声发射和应变的变化.试验结果表明，孔洞群倾角的增大有利于岩石的初始损伤程度，削弱起裂应力;初始裂纹起裂方向约为90 °，延伸角度约为75 °，与条形贯通裂纹近似为90 °，裂纹发展与孔洞群起裂的关系加强。具体表现为：当起裂角为30 °时，腔组中腔体间裂纹沿平行于外载荷的方向相对独立地沿着发展;当起裂角为75 °时，腔组中腔体间裂纹可相互贯通，在剪切机制破裂的作用下可沿腔组倾角沿着发生滑移。随着腔组倾角的增大，峰值应力处的声发射能量波动频率增大，应力降明显。孔洞群倾角越大，能量积聚越明显，岩石损伤越严重;当孔群角为30 °或75 °时，条形贯通断裂面下方局部区域的峰值应变约为孔群角为45 °和60 °时的3倍，表明在该角度应变片监测的局部区域容易产生裂缝，裂缝的进一步发展削弱了岩石的强度，从而增加了工程质量重大破坏的概率。研究成果对穿越天然和人工缺陷岩体的地下工程，包括隧道和防空洞的灾害防治具有重要的参考价值。
To study the evolution mechanism of cracks in rocks with multiple defects, rock-like samples with multiple defects, such as strip-shaped through-going cracks and cavity groups, are used, and the crack propagation law and changes in AE (acoustic emission) and strain of cavity groups under different inclination angles are studied. According to the test results, an increase in the cavity group inclination angle can facilitate the initial damage degree of the rock and weaken the crack initiation stress; the initial crack initiation direction is approximately 90 degrees, and the extension angle is approximately 75 similar to 90 degrees from the strip-shaped through-going cracks; thus, the relationship between crack development and cavity group initiation strengthens. The specific performance is as follows: when the initiation angle is 30 degrees, the cracks between the cavities in the cavity group develop relatively independently along the parallel direction of the external load; when the angle is 75 degrees, the cracks between the cavities in the cavity group can interpenetrate, and slip can occur along the inclination of the cavity group under the action of the shear mechanism rupture. With the increase in the inclination angle of the cavity group, the AE energy fluctuation frequency at the peak stress increases, and the stress drop is obvious. The larger the cavity group inclination angle is, the more obvious the energy accumulation and the more severe the rock damage; when the cavity group angle is 30 degrees or 75 degrees, the peak strain of the local area below the strip-shaped through-going fracture plane is approximately three times that when the cavity group angle is 45 degrees and 60 degrees, indicating that cracks are easily generated in the local area monitored by the strain gauge at this angle, and the further development of the cracks weakens the strength of the rock, thereby increasing the probability of major engineering quality damage. The research results will have important reference value for hazard prevention in underground engineering projects through rock with natural and artificial defects, including tunnels and air-raid shelters.