高频振捣对混凝土抗冻性的影响机理及在寒区隧道施工中的应用

发布时间：2018-08-31 10:03

【摘要】：为探讨寒区隧道二衬施工新工艺新方法,以兰新铁路二线甘青段LXS-8标铁路隧道为工程依托,针对高频振捣系统在隧道二衬施工中结构可靠性和性能稳定性开展试验研究。在系统分析高频振捣对混凝土抗冻性影响机理的基础上,从设备选型、安装调试、振捣时间控制以及混凝土抗冻性能试验等方面入手,制定高频振捣施工工艺,总结施工注意事项和寒区隧道二衬施工的保温措施。试验对坍落度为16.8 cm,水胶比为0.37的C35混凝土进行多次振捣试振,最终确定持续振动为25~40 s的情况下,可以取得理想的表观质量和混凝土强度;同时抗冻性试验表明,冻融循环300次后,混凝土质量损失率均保持在3%以下,相对动弹性模量在80%~90%,达到F300抗冻等级。试振试验和检测结果表明,高频振捣技术可以推广应用于寒区冻土隧道的二衬施工。
[Abstract]:In order to discuss the new technology and new method of the second lining construction of tunnel in cold area, based on the LXS-8 standard railway tunnel in Ganqing section of the second line of Lanxin railway, the structural reliability and performance stability of the high-frequency vibrating system in the construction of the second lining of the tunnel are studied experimentally. Based on the systematic analysis of the mechanism of the influence of high frequency vibration on the frost resistance of concrete, from the aspects of equipment selection, installation and debugging, vibration time control and concrete antifreeze performance test, the construction technology of high frequency vibration is established. This paper summarizes the matters needing attention in construction and the insulation measures for the construction of the second lining of the tunnel in cold area. C35 concrete with a slump of 16.8 cm, water / binder ratio of 0.37 has been vibrated for several times, and the continuous vibration is determined to be 25 ~ 40 s, the ideal apparent quality and concrete strength can be obtained, and the freezing resistance test shows that, After 300 cycles of freeze-thaw cycle, the mass loss rate of concrete is kept below 3%, and the relative dynamic elastic modulus is 80%, which reaches the F300 grade. The results of vibration test and test show that the high frequency vibration technique can be applied to the construction of second lining of frozen soil tunnel in cold region.
【作者单位】：西南交通大学交通隧道工程教育部重点实验室;中国中铁二局第四工程有限公司;
【基金】：中央高校基本科研业务专项基金项目(SWJTU11ZT33) 教育部创新团队发展计划项目(IRT0955)
【分类号】：U454

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