Cracking and Stress-Strain Behavior of Rock-Like Material Containing Two Flaws Under Uniaxial Compression
Cracking and Stress-Strain Behavior of Rock-Like Material Containing Two Flaws Under Uniaxial Compression
复制标题
含有两个缺陷的类岩石材料在单轴压缩下的开裂和应力应变行为
DOI：
10.1007/s00603-016-0932-1
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发表时间：
2016-07-01
影响因子：
6.2
通讯作者：
Tang, Jingzhou
中科院分区：
文献类型：
--
作者：
Zhao, Yanlin;Zhang, Lianyang;Tang, Jingzhou
本文研究了含双缺陷岩石类材料的开裂和应力应变行为，特别是裂纹尖端附近的局部应变集中。对含两个裂纹的类岩石试件进行了单轴压缩试验，在裂纹尖端附近安装应变片，测量单轴压缩载荷下的局部应变集中。在实验中观察到四种不同类型的裂纹（翼裂纹、反翼裂纹、共面剪切裂纹和斜向剪切裂纹）和七种裂纹聚并模式（T1和T2; S1和S2;以及TS 1、TS 2和TS 3）。裂纹合并的类型与缺陷的几何形状有关。随着岩桥韧带角的增大，裂纹的贯通方式由S型向TS型再向T型变化。含双缺陷试件的应力-应变曲线与裂纹的扩展和贯通过程密切相关。应变测量结果表明，裂纹尖端以下或以上的局部拉应变集中导致翼裂纹或反翼裂纹，而裂纹尖端附近的局部压应变集中则与剪切裂纹有关。测得的局部拉伸应变显示出在翼裂纹和反翼裂纹的起始处的跳跃，反映了翼裂纹和反翼裂纹通过应变计传播的瞬间打开。在翼裂纹和反翼裂纹的扩展过程中，测得的局部拉应变逐渐增加，很少跳跃，这意味着翼裂纹和反翼裂纹的张开变形发生在一个稳定的方式。剪切裂纹的萌生伴随着一个突然的大的压应变跃变，然后以不稳定的方式快速扩展，最终导致试件的破坏。
This paper investigates the cracking and stress-strain behavior, especially the local strain concentration near the flaw tips, of rock-like material containing two flaws. A series of uniaxial compression tests were carried out on rock-like specimens containing two flaws, with strain gauges mounted near the flaw tips to measure the local strain concentration under the uniaxial compressive loading. Four different types of cracks (wing cracks, anti-wing cracks, coplanar shear cracks and oblique shear cracks) and seven patterns of crack coalescences (T1 and T2; S1 and S2; and TS1, TS2 and TS3) are observed in the experiments. The type of crack coalescence is related to the geometry of the flaws. In general, the crack coalescence varies from the S-mode to the TS-mode and then to the T-mode with the increase of the rock bridge ligament angle. The stress-strain curves of the specimens containing two flaws are closely related to the crack development and coalescence process. The strain measurements indicate that the local tensile strain concentration below or above the pre-existing flaw tip causes wing or anti-wing cracks, while the local compressive strain concentration near the flaw tip is related to the shear crack. The measured local tensile strain shows a jump at the initiation of wing- and anti-wing cracks, reflecting the instant opening of the wing- and anti-wing crack propagating through the strain gauge. During the propagation of wing- and anti-wing cracks, the measured local tensile strain gradually increases with few jumps, implying that the opening deformation of wing- and anti-wing cracks occurs in a stable manner. The shear cracks initiate followed by a large and abrupt compressive strain jump and then quickly propagate in an unstable manner resulting in the failure of specimens.