Fracture behaviour of central-flawed rock plate under uniaxial compression
Fracture behaviour of central-flawed rock plate under uniaxial compression
复制标题
单轴压缩下中心缺陷岩板的断裂行为
DOI：
10.1016/j.tafmec.2020.102503
复制
发表时间：
2020-04-01
影响因子：
5.3
通讯作者：
Liu, Yan
中科院分区：
文献类型：
--
作者：
Wang, Yixian;Zhang, Hui;Liu, Yan
断层破碎带是山岭隧道开挖中常见的工程地质条件，往往给工程施工带来很大困难。针对这一问题，对含中心孔洞和孔洞边缘缺陷的花岗岩试件进行了单轴压缩试验。通过理论分析和扩展有限元模拟，研究了裂纹的萌生机理。试验结果表明，试样的力学参数和裂纹类型随裂纹倾角的变化而明显变化。与完整试件相比，中心孔和孔边缺陷对试件的强度等力学性能有较大的削弱作用，且随着缺陷倾角的增大，削弱作用逐渐减弱。当裂纹倾角较小时，拉伸裂纹所占比例较高，导致试件发生拉伸破坏。随着裂纹倾角的增大，剪切裂纹逐渐占主导地位，导致试件发生剪切破坏。此外，理论分析和数值模拟结果表明，实验中出现的翼裂纹起裂角与理论和模拟结果完全一致。计算结果表明，裂纹倾角为15 °和75 °的试件裂纹尖端的拉应力低于其他试件，这可能是导致翼裂纹不产生的原因。
Fault fracture zone is a common engineering geological condition in mountain tunnel excavation, which often brings great difficulties to engineering construction. Thus, uniaxial compression experiments were carried out on the granite specimens with a central hole and hole edge flaws to investigate such engineering problems. And the crack initiation mechanism was studied by theoretical analysis and Extended Finite Element Methods (XFEM) simulation. The experimental results show that the mechanical parameters and crack types of the specimens distinctly vary with the flaw inclination. The mechanical properties of specimens such as strength are greatly weakened by the central hole and hole edge flaws compared with those of intact specimens, and the weakening effect decreases gradually with the increase of flaw inclination angle. When the inclination angle of flaw is small, the proportion of tensile cracks is high, resulting in tensile failure of specimens. While as the inclination angle of flaw increases, shear cracks gradually dominate, leading to shear failure in the specimen. In addition, the results of theoretical analysis and numerical simulation show that the wing crack initiation angle that appeared in the experiment are completely consistent with the theoretical and simulation results. And it is suggested by numerical results that the tensile stress at the flaw tip of specimens with flaw inclination angle of 15 degrees and 75 degrees is lower than that of other specimens, which may cause the absence of wing cracks.