盾构隧道功能梯度混凝土管片保护层设计及性能

针对武汉长江隧道工程高压富水的环境要求,以提高构件的耐久性,延长其服役寿命为主要目标,引入功能梯度材料设计原理,对盾构隧道管片外保护层材料进行单独设计.对普通混凝土保护层、高性能混凝土保护层及无细观界面过渡区水泥基材料(MIF)保护层等3种体系分别进行了对比分析及相关性能研究.结果表明,无细观界面过渡区水泥基材料表现出更为优异的性能,氯离子扩散系数减小一个数量级,而材料服役寿命增长10倍以上;力学性能及体积稳定性优良,完全满足工程所需强度,整体结构的体积变形匹配性良好,表面未见开裂,有效保证了结构构件的高耐久、长寿命.

Design and property of covering layer of functionally graded concrete segment used in shield tunneling

With the environment of high pressure and enrich water of Wuhan Yangtze River Tunnel, for the aim of improving the durability of structural member and extending service life, the specific technology was applied in the design of covering layer materials of segment used in shield tunneling in terms of the principle of functionally graded materials (FGM). Furthermore, the contrastive analysis and service property were investigated in three systems of the ordinary concrete covering layer, the high-performance concrete covering layer and the Meso-defect interface transition zone free cement based material (MIF) covering layer. The results indicate that MIF shows excellent performance compared with other materials, and the chloride diffusion coefficient decreases one order of magnitude, while the service life increases more than ten fold. On the other hand, the mechanical property and the volume stability of the MIF covering layer are excellent and meet requirements of design, showing better compatibility in the volume deformation of the whole structure; and the cracking of concrete surface cannot be found, ensuring the higher durability and longer life of structural member effectively.