Substantial concrete pouring is common in large-cross-section station tunnels and releases a considerable amount of hydration heat, which negatively affects the quality and reliability of lining structures. Extensive research on the hydration heat of concrete linings in underground tunnels has not yet been conducted. This study investigated the structural temperature and stress caused by hydration heat. The numerical simulations showed a maximum temperature differential of 24.6°C between the inner and outer surfaces during the concrete pouring phase, which could lead to non-structural cracking. The temperature stress of the lining was not significantly affected by the longitudinal pouring length but was closely related to the timing of formwork removal. Shortening the formwork removal time reduced the temperature stress on the structure. Layered pouring and embedded cooling of water pipes can mitigate the effect of hydration heat on the lining, with the latter providing better cooling than the former. A layered pouring scheme with a controlled thickness of less than 1 m and pouring intervals greater than five days should be implemented to optimise construction efficiency and cooling performance. These findings can be used to control the hydration temperature and enhance the construction quality of mass concrete in tunnel linings.

中文翻译：

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超大断面隧道衬砌混凝土水化热对结构应力的影响及其缓解措施


在大横截面车站隧道中，大量的混凝土浇筑很常见，并释放出大量的水化热，这对衬砌结构的质量和可靠性产生了负面影响。尚未对地下隧道中混凝土衬砌的水化热进行广泛研究。本研究调查了水化热引起的结构温度和应力。数值模拟显示，在混凝土浇筑阶段，内外表面之间的最大温差为 24.6°C，这可能导致非结构性开裂。衬砌的温度应力受纵向浇筑长度影响不显著，但与模板拆除时间密切相关。缩短模板拆除时间降低了结构上的温度应力。分层浇注和嵌入式冷却水管可以减轻水合热对衬里的影响，后者比前者提供更好的冷却效果。应实施分层浇筑方案，将厚度控制在小于 1 米，浇筑间隔大于 5 天，以优化施工效率和冷却性能。这些发现可用于控制隧道衬砌中大体积混凝土的水化温度并提高其施工质量。