In this paper, to study the influence of grouting on meso-failure mechanism, acoustic emission (AE) localization technique was used to monitor the micro-cracking during the uniaxial compression tests on single flawed sandstone specimens with or without grouting. Due to the inhomogeneous geometrical structure of the flawed specimens, the mesoscopic damage evolution is also inhomogeneous during the loading process. As a result, the wave velocity of the specimens varied temporally and spatially, which greatly increased the difficulty in accurate AE localization. To solve this problem, the wave velocities versus the axial load for the studied sandstone were first measured, and the stress concentration effect near the flaw was also theoretically analyzed. Accordingly, the localization arithmetic was also improved to match the complex wave velocity field. Results show that compared to the specimens without grouting, more microcracks (particularly the shear microcracks) are induced in the grout-infilled specimens prior to the final failure of the specimens. Moreover, the effect of grouting on microcrack initiation also varies with the oblique angle of the flaw. For θ (flaw inclination) ≤30°, grouting significantly increases the shear microcrack at macrocrack propagation stage which states that the axial tensile cracking was limited by the supporting effect of the grout material and made the failure mode trend to shear mode. For θ = 45° and 60°, grouting improved the ratio of shear microcrack during the whole failure process, indicating that the direction of maximum shear stress is close to the flaw direction. Hence, failure develops in stable shear mode. For θ = 75° and 90°, the primary microcrack generated during the first macrocrack initiation changed to shear mode, but the grouting has little influence on the subsequent crack propagation. So that, the reinforcement effect is poor in this set of specimens.

在本文中，为了研究注浆对细观破坏机制的影响，声发射 (AE) 定位技术被用于监测单轴压缩试验过程中的微裂纹，这些试件在注浆或不注浆的情况下有缺陷。由于缺陷试样几何结构的不均匀性，加载过程中的细观损伤演化也是不均匀的。结果，标本的波速在时间和空间上发生变化，这大大增加了精确AE定位的难度。为了解决这个问题，首先测量了所研究砂岩的波速与轴向载荷的关系，并对裂纹附近的应力集中效应进行了理论分析。因此，定位算法也得到改进，以匹配复杂的波速场。结果表明，与没有灌浆的试样相比，在试样最终失效之前，灌浆试样中会诱发更多的微裂纹（特别是剪切微裂纹）。此外，注浆对微裂纹萌生的影响也随裂纹倾斜角度的不同而变化。为了θ（缺陷倾角）≤30°，注浆显着增加了宏观裂纹扩展阶段的剪切微裂纹，说明轴向拉伸裂缝受灌浆材料支撑作用的限制，使破坏模式趋向于剪切模式。对于θ = 45°和60°，注浆提高了整个破坏过程中剪切微裂纹的比例，表明最大剪应力方向接近缺陷方向。因此，破坏以稳定的剪切模式发展。对于θ =75°和90°，第一次宏观裂纹萌生时产生的初级微裂纹转变为剪切模式，但注浆对后续裂纹扩展影响不大。因此，该组试件的加固效果较差。