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为了探讨高温下隧道衬砌混凝土材料性能的衰减规律和管片结构的高温损伤规律,进行了衬砌混凝土材料和构件的火灾烧损试验。结果表明,高性能混凝土的抗压强度、弹性模量和抗渗性能都随温度升高而迅速劣化,抗渗性能的降幅大于力学性能。掺入聚丙烯纤维对衬砌混凝土的高温爆裂有明显抑制效果,粗骨料的品种和颗粒形状对混凝土的高温损伤形式有明显影响。最后,在经典火灾评价模型的基础上,加入爆裂面积率、抗渗性能损失两个损伤指标特征,对试验中的衬砌管片火灾损伤进行评估。火灾作用2 h后,衬砌管片火灾损伤程度介于III~IV级(严重损伤与极度损伤)之间。
In order to study the attenuation law of the performance of tunnel lining concrete at high temperature and the high temperature damage of the pipe structure, the fire damage test of lining concrete and its components was carried out. The results show that the compressive strength, elastic modulus and impermeability of high performance concrete all deteriorate rapidly with the increase of temperature, and the decrease of impermeability is larger than the mechanical properties. The incorporation of polypropylene fiber has a significant inhibitory effect on the high temperature burst of the lining concrete, and the variety and particle shape of the coarse aggregate have a significant effect on the high temperature damage form of the concrete. Finally, based on the classic fire evaluation model, the damage area ratio and impermeability are added to damage the two damage indexes, and the fire damage of the lining segment in the test is evaluated. After 2 h of fire, the damage degree of the lining pipe pieces was between Grade III and IV (severe and extreme damage).