Wu Chaolei, Jiang Lishuai, Zhao Yang, Wu Qi, Yang Yiming, Peng Xiaohan, Li Pimao
College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao 266590, China.
State Key Laboratory of Mining Disaster Prevention and Control, Shandong University of Science and Technology, Qingdao 266590, China.
Materials (Basel). 2024 Dec 18;17(24):6180. doi: 10.3390/ma17246180.
The shear failure of rock masses is one of the primary causes of underground engineering instability. The shear mechanical behavior of rocks at different sizes is of great significance for studying the shear failure pattern of engineering rock masses. However, due to the presence of various joints and defects in natural rocks, the obtained rock specimens exhibit significant discreteness, making it difficult to customize specimen sizes for size effect studies. In recent years, 3D printing (3DP) technology has gained widespread application in rock mechanics tests due to its high printing precision and ability to form specimens in a single step with minimal discreteness. Among these, specimens prepared using sand-powder 3DP exhibit elastoplastic mechanical characteristics similar to those of natural rocks. Therefore, this study utilized sand-powder 3DP to prepare rock-like specimens of four different sizes and conducted compression shear tests under three different shear velocities. The shear strength, shear strain, and wear of the shear surfaces were analyzed as functions of specimen size and shear velocities. The results indicate that under the same shear velocity, the shear strength of the specimens is negatively correlated with specimen size. The peak shear strain is generally unaffected by shear velocities, but it increases initially and then decreases with increasing specimen size. As specimen size increases, the degree of specimen damage intensifies, and larger specimens are more prone to developing derived fractures. This study broadens the application of sand-powder 3DP technology in investigating the shear mechanical properties of soft rocks, offering novel insights into the study of size effects in rock mechanics. However, the current research does not encompass tests on 3D-printed rock specimens with varying printing directions, nor does it delve into the role of fractures in size effect analyses. Future investigations will aim to address these limitations, thereby advancing the applicability of 3D printing technology in rock mechanics research and enhancing its contributions to the field.
岩体的剪切破坏是地下工程失稳的主要原因之一。研究不同尺寸岩石的剪切力学行为对于探究工程岩体的剪切破坏模式具有重要意义。然而，由于天然岩石中存在各种节理和缺陷，所获取的岩石试样离散性显著，难以定制试样尺寸以开展尺寸效应研究。近年来，3D打印（3DP）技术因其打印精度高且能一步成型离散性极小的试样，在岩石力学试验中得到广泛应用。其中，采用砂粉3DP制备的试样呈现出与天然岩石相似的弹塑性力学特性。因此，本研究利用砂粉3DP制备了四种不同尺寸的类岩石试样，并在三种不同剪切速度下进行了压缩剪切试验。分析了剪切强度、剪切应变和剪切面磨损随试样尺寸和剪切速度的变化情况。结果表明，在相同剪切速度下，试样的剪切强度与试样尺寸呈负相关。峰值剪切应变一般不受剪切速度影响，但随试样尺寸增大先增大后减小。随着试样尺寸增大，试样损伤程度加剧，较大试样更易产生衍生裂缝。本研究拓宽了砂粉3DP技术在软岩剪切力学性能研究中的应用，为岩石力学尺寸效应研究提供了新的见解。然而，目前的研究未涉及不同打印方向的3D打印岩石试样试验，也未深入探讨裂缝在尺寸效应分析中的作用。未来的研究将致力于解决这些局限性，从而提高3D打印技术在岩石力学研究中的适用性，并增强其对该领域的贡献。
