摘   要：通过调整超缓凝剂掺量（1.0%、1.2%、1.4%、1.6%、1.8%、2.0%、2.2%）、粉煤灰掺量（0、10%、15%、25%）、脱附土掺量（0、20%、40%、60%、80%、100%）、砂率（36%、38%、40%、44%）优选了地铁盖挖逆作法专用混凝土配合比，并对其凝结时间、工作性与力学性能进行了测试，分析了微观形貌与水化机理。结果表明：随着超缓凝剂掺量的增加，混凝土的凝结时间延长，坍落度、扩展度均增加，7 d抗压强度降低，14~56 d抗压强度先增后降；随着粉煤灰掺量的增加，混凝土的抗压强度先增后降；随着脱附土掺量的增加，混凝土的抗压强度降低；随着砂率的提高，混凝土的抗压强度先增后降；配合比最优组合为超缓凝剂掺量1.6%、粉煤灰掺量15%、脱附土掺量40%、砂率40%，以此制备的混凝土具有良好的工作性，较高的早期抗压强度，且后期抗压强度不倒缩；超缓凝剂及矿物掺合料的掺入降低了水泥水化放热温度峰值，延长了水泥的水化进程，且不会影响混凝土后期力学性能发展。

Abstract: By adjusting the dosage of super retarders (1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 2.2%), fly ash dosage (0, 10%, 15%, 25%), detachment soil dosage (0, 20%, 40%, 60%, 80%, 100%), and sand ratio (36%, 38%, 40%, 44%), the special concrete mix proportion for subway cover excavation reverse method was optimized. The setting time, workability, and mechanical properties were tested, and the microstructure and hydration mechanism were analyzed. The results show that with the increase of the dosage of super retarder, the setting time of concrete is prolonged, and the slump and expansion increase. The compressive strength decreases at 7 d, and increases first and then decreases at 14~56 d. With the increase of fly ash dosage, the compressive strength of concrete first increases and then decreases. With the increase of detachment soil dosage, the compressive strength of concrete decreases. With the increase of sand ratio, the compressive strength of concrete first increases and then decreases. The optimal mix proportion is 1.6% dosage of super retarder, 15% dosage of fly ash, 40% dosage of detachment soil, and 40% of sand ratio. The concrete prepared from this has good workability, high early compressive strength, and no shrinkage in later compressive strength. The addition of super retarders and mineral admixtures reduces the peak heat release temperature of cement hydration, prolongs the hydration process of cement, and does not affect the later mechanical performance development of concrete.