A compression module system placed under a microscope was utilized to conduct uniaxial compression testing of sandstone samples. The test system can acquire the image of crack propagation on the specimen surface in real time. The focus of this study was to analyze how the motion of sandstone composition particles affect the failure mechanism of the samples under minimal loading rates. The results indicate that the load displacement curves align with the macroscopic failure laws under different loading rates. Furthermore, the lower the loading rate, the greater the deformation and crushing degree of sandstone during failure. The failure mode becomes more complex and gradually transitions from tension failure to shear-tension failure. The crack evolution of sandstone was caused by the uncoordinated movement of its components, and the weak structure induces cracks under the action of external load. Microcracks are initially generated at the interface between mineral particles and the sandstone matrix and propagate along the boundary between mineral and matrix. The interaction between component particles in sandstone leads to the connection break between particles which forms microcracks, and results in local deformation of the sample. The aggregation of multiple cracks leads to the instability and failure of sandstone.

利用放置在显微镜下的压缩模块系统对砂岩样品进行单轴压缩测试。测试系统可以实时获取试件表面裂纹扩展的图像。本研究的重点是分析砂岩成分颗粒的运动如何影响最小加载速率下样品的破坏机制。结果表明，不同加载速率下的载荷位移曲线符合宏观破坏规律。此外，加载速率越低，破坏时砂岩的变形和破碎程度越大。破坏模式变得更加复杂，并逐渐从拉力破坏转变为剪拉破坏。砂岩的裂纹演化是由于其各组分的不协调运动造成的，软弱结构在外荷载作用下诱发裂纹。微裂纹最初产生于矿物颗粒与砂岩基质之间的界面处，并沿着矿物与基质之间的边界扩展。砂岩中各组分颗粒之间的相互作用导致颗粒之间的连接断裂，形成微裂纹，导致样品的局部变形。多条裂缝的聚集导致砂岩失稳破坏。