摘要
设置层间聚氨酯板是寒区隧道防冻的常用措施之一。文中采用室内模拟实验方法对实际工程条件下寒区隧道层间聚氨酯保温板的挤压浸水冻融特性进行了研究。实验结果表明:静力反复作用可导致聚氨酯结构破坏,压缩率增大,结构破坏后吸水率受控于压缩率;浸水冻融与静力挤压共同作用,会显著加剧对聚氨酯结构的破坏,压缩率和吸水率显著增大,影响最大的是饱和吸水,其次是自由吸水,最小是约束饱和吸水。鉴于工程条件下层间聚氨酯受到静力挤压、浸水和短周期冻融是普遍现象,抗压性能逐步降低、吸水性能逐步增强亦难以避免,必然降低聚氨酯的耐久性,进而影响寒区隧道的保温效果、围岩结构稳定与安全,据此不建议采用层间保温隔热方法进行防冻。
Interlayer polyurethane(PU)insulation layer is a main measure used in cold region tunnels for freeze-proofing.The characteristics of PU were studied by laboratory test method considering the actual engineering conditions including the extrusion,immersion and freeze-thaw.Experiment results reveal that:repeated extrusion by load can lead to the structural damage of the PU,and the increase of compress ratio,and the water absorption ratio is controlled by compress ratio;combined action of extrusion,immersion and freeze-thaw can sharply promote the structural damage of the PU,and increase the compress ratio and water absorption ratio.Among which,the influence of the saturated water absorption is the most,secondly the free water absorption,next constraint saturated water absorption.As the extrusion,immersion and freeze-thaw phenomenon are widely existed in actual engineering,so the compressive properties decrease and the water absorption properties increase will widely happen to tunnels in cold region.These will sharply shortens the lifetime of PU,and affect its heat preservation effect,the stability and safety of the structure and rock of tunnel.Therefore,PU is not recommended to use as interlayer insulation for tunnels in cold region.
作者
汤贵海
伍毅敏
张镇国
张庆宁
TANG Gui-hai;WU Yi-min;ZHANG Zhen-guo;ZHANG Qing-ning(China Railway 22 nd Construction Bureau 1 st Engineering Co.,Ltd.,Beijing 100040,China;School of Civil Engineering,Central South University,Changsha 410075,China;Shandong Provincial Communications Planning and Design Institute,Jinan 250031,China)
出处
《西安科技大学学报》
CAS
北大核心
2018年第2期323-329,共7页
Journal of Xi’an University of Science and Technology
基金
国家自然科学基金(51478473
51578550)
关键词
寒区隧道
聚氨酯板
冻融特性
tunnel in cold region
polyurethane insulation
performance under freeze-thaw cycles
