护盾式全断面掘进机（Tunnel Boring Machine，简称TBM）因具有掘进效率高、对围岩扰动小、安全性高等优点而被广泛应用于隧洞工程，其通过安装预制管片来对开挖围岩进行衬砌，并向衬砌管片与围岩之间的间隙回填水泥基材料来形成“回填层+衬砌管片”复合支护结构。在高地应力、大埋深、复杂地质的隧洞工程中，开挖过程容易发生岩爆、大变形、涌水等问题，需要对围岩进行及时、高质量的回填支护。然而目前常用的豆砾石回填灌浆技术存在回填密实度低、支护滞后、工序繁杂等不足，常常难以满足相关要求。同时，水泥基材料被回填至围岩与管片之间后，在水化硬化期间会受到围岩的持续压缩，但现有研究大多忽略了外部压缩对材料早龄期（早于7 d）性能的影响，缺乏对其物理机制和工程影响的深入认识。论文围绕实际工程需要，引入自密实施工技术对护盾式TBM隧洞的回填支护技术进行优化升级，通过开展侧限压缩试验研究外部压缩对早龄期自密实材料性能的影响，并建立了可以考虑压缩影响的分析模型来研究早龄期自密实材料的回填支护效果，具有一定的创新价值和工程意义。具体研究工作和创新成果包括：1. 提出了一种基于自密实回填的护盾式TBM隧洞快速支护技术。设计制造了一种充气止浆环新结构，并结合数值模拟对其工作机理进行了解释；研制了多种自密实新材料，并依托室内试验证实了其作为隧洞回填材料的可行性；提出了基于自密实回填的快速支护新工法，并依托工程现场试验证实了其可行性。2. 基于自主研发的早龄期水泥基材料侧限压缩试验设备，发现了水化动力学与自密实混凝土早期力学性能的关系，揭示了不同压缩条件对自密实混凝土宏微观性能的影响规律，并针对侧限弹模增长与蠕变参数演变建立了经验模型。3. 基于自主研发的早龄期水泥基材料侧限压缩试验设备，揭示了不同堆石率下堆石体的侧限压缩特性及其机理，发现了水化动力学与堆石混凝土早期力学性能的关系，揭示了不同堆石率、不同压缩条件对堆石混凝土宏微观性能的影响规律，并针对侧限弹模增长与蠕变参数演变建立了对应的经验模型。4. 建立了可考虑早龄期压缩影响的自密实材料本构及“围岩-支护”相互作用分析模型，基于此揭示了“围岩-支护”早期相互作用机制，得到了不同回填材料在不同隧洞条件下的支护效果差异，并总结了不同类型回填材料的适用工程条件。
The shield-type Tunnel Boring Machine (TBM) is widely used in tunnel engineering due to its high excavation efficiency, low disturbance to surrounding rocks, and high safety. It uses precast concrete segments to line the excavated rock, and backfills the gap between the lining and the rock with cement-based material to form a composite support structure consisting of a filling layer and the lining. In tunnel engineering with high ground stress, large buried depth, and complex geology, problems such as rock burst, large deformation, and water gushing are prone to occur during the excavation process. Thus, timely and high-quality backfill support is needed for the surrounding rock. However, the commonly used bean gravel backfill grouting technology has shortcomings such as low backfill density, delayed support, and complicated procedures, which often fail to meet the relevant requirements. Moreover, after being backfilled between the surrounding rock and the segment, cement-based materials will be subjected to continuous compression of the surrounding rock during hydration. However, most existing studies have ignored the impact of external compression on the early age (earlier than 7 d) performance of the cement-based materials. This leads to a lack of in-depth understanding of the physical mechanisms and engineering impacts.Focusing on practical engineering needs, this thesis introduces self-compacting construction technology to optimize and upgrade the backfill and support technology for shield-type TBM tunnels. Through conducting oedometric compression tests, this thesis studies the impact of external compression on the performance of early-age self-compacting materials, and establishes an analysis model that can consider the effect of compression to investigate the support effect of early-age self-compacting materials. The specific research work and innovative achievements include:1. A shield-type TBM tunnel rapid support technology based on self-compacting backfill is proposed. A new structure of inflatable grout stop ring was designed and manufactured, and its working mechanism was explained by numerical simulation. A variety of self-compacting materials have been developed, and their feasibility as tunnel backfill materials has been confirmed through laboratory tests. A new construction method of rapid support based on self-compacting backfill is proposed, and its feasibility has been verified through field tests.2. Based on the independently developed oedometric compression test equipment for early-age cement-based materials, the relationship between hydration kinetics and early-age mechanical properties of self-compacting concrete was discovered, and the influence laws of different compression conditions on the macro and micro properties of self-compacting concrete were revealed. Empirical models were established for the growth of oedometric elastic modulus and the evolution of creep parameter.3. Based on the independently developed oedometric compression test equipment for early-age cement-based materials, the oedometric compression characteristics and mechanisms of rockfill under different rockfill density were revealed, the relationship between hydration kinetics and early-age mechanical properties of rock-filled concrete was discovered, and the effects of different rockfill density and different compression conditions on the macro and micro properties of rock-filled concrete were revealed. Corresponding empirical models were established for the growth of oedometric elastic modulus and the evolution of creep parameter.4. A constitutive model of self-compacting materials and a "surrounding rock-support" interaction analysis model that can consider the impact of early-age compression have been established. Based on this, the early interaction mechanism of "surrounding rock-support" has been revealed, the differences in support effects of different backfill materials under different tunnel conditions have been obtained, and the applicable engineering conditions for different types of backfill materials have been summarized.
