高地热环境对铁路隧道混凝土性能的影响机理及评价指标

Influence Mechanism and Evaluation Index of High Geothermal Environment on Performance of Railway Tunnel Concrete

针对高地热隧道内铁路工程混凝土的性能劣化问题,本文系统总结了高地热环境对铁路工程隧道喷射混凝土、隧道衬砌混凝土和无砟轨道混凝土的影响,对比了不同结构类型隧道混凝土的劣化特征,提出高地热、列车荷载或侵蚀性盐类耦合作用下的铁路隧道混凝土劣化是未来高地热铁路隧道需要关注的重点。从孔结构、微观特征和物相组成等角度得出,高地热环境下铁路隧道混凝土性能劣化的原因是高温下混凝土浆体结构疏松以及水化产物分布不均匀。建议以混凝土导热系数、强度损失比作为高地热环境铁路隧道混凝土性能的评价指标,指出具有较低导热系数的相变材料混凝土和地质聚合物混凝土是未来解决高地热环境下铁路隧道混凝土性能劣化问题的有效途径,可为高地热环境下铁路隧道混凝土的施工和安全服役提供参考。

To address the problem of deterioration of railway tunnel concrete under high geothermal environment,this paper systematically lists the effects of high geothermal environment on railway tunnel shotcrete,tunnel lining concrete and ballastless track concrete,and then compares features of deterioration of tunnel concrete.Furthermore,it is proposed that the accelerated deterioration of railway tunnel concrete under the coupling effect of high geothermal and train load or high geothermal and corrosive salts is a problem that should be paid more attention to in the future.From the perspective of pore structure,microscopic characteristics and phase composition,it is concluded that the deterioration of concrete performance in railway tunnel under high geothermal environment is caused by loose concrete slurry structure and uneven distribution of hydration products.Therefore,the paper proposes the thermal conductivity and strength loss rate as evaluation indexes for the performance of railway tunnel concrete,with a view to providing reference for the construction and safe operation of railway tunnel concrete under high geothermal environment.