为提升盾构渣土的资源化利用率，改善再生混凝土的力学性能并研究其破坏机制，设计无粗骨料（NCS）、单粒径（1C10）、双粒径（2C15）和级配良好（3C20）4组混凝土，通过单轴压缩试验与数字图像相关（DIC）技术，分析28 d与56 d龄期下的强度发展与破坏机制。结果表明： 1）NCS组28 d抗压强度为54.19 MPa，满足C50设计强度要求，但56 d强度发展有限，裂缝宽度最大，表现出明显的脆性破坏特征； 2）1C10组56 d抗压强度最高（79.76 MPa），裂缝扩展曲折，呈多裂缝韧性破坏； 3）2C15组压缩韧性指数最优，表现出良好的韧性与能量吸收能力； 4）3C20组强度显著退化（43.30 MPa），未达到设计强度，裂缝贯通骨料，破坏呈明显脆性。虽然NCS组能满足基本强度要求，但采用单粒径或双粒径级配可有效优化裂缝路径与破坏模式，推荐在实际应用中控制骨料最大粒径不超过15 mm，以保障盾构渣土混凝土的强度与耐久性要求。

To enhance the resource utilization of shield tunnel muck and improve the mechanical properties of recycled concrete while investigating its failure mechanism, four concrete mix proportions—no coarse aggregate (NCS), single-sized aggregate (1C10), double-sized aggregate (2C15), and well-graded aggregate (3C20)—are designed. Uniaxial compression tests and digital image correlation (DIC) techniques are employed to analyze the strength development and failure mechanisms at 28-day and 56-day curing ages. The results show the following: (1) The NCS group achieves a 28-day compressive strength of 54.19 MPa, meeting the C50 design strength requirement. However, its 56-day strength development is limited, exhibiting the largest crack width and significant brittle failure characteristics. (2) The 1C10 group achieves the highest 56-day compressive strength (79.76 MPa), with tortuous crack propagation and a multi-crack ductile failure mode. (3) The 2C15 group demonstrates the optimal compressive toughness index, indicating excellent toughness and energy absorption capacity. (4) The 3C20 group shows significant strength regression (43.30 MPa), failing to meet the design strength requirement, with cracks penetrating aggregates and exhibiting obvious brittle failure. While the NCS group meets the basic strength requirement, but single-sized or double-sized aggregate gradations can effectively optimize crack paths and failure modes. It is recommended to control the maximum aggregate size not exceeding 15 mm in practical applications to ensure the strength and durability requirements of concrete made from shield muck.