摘要
为提高铁路隧道施工用喷射混凝土综合性能,通过试验开展铁路隧道施工喷射混凝土配合比优化研究。通过探索性试验、聚丙烯纤维掺量单因素试验、速凝剂掺量单因素试验、弯曲韧性试验等优化喷射混凝土性能。研究结果表明,聚丙烯纤维在喷射混凝土中主要发挥二次骨架效应和吸收应变能效应。与未掺聚丙烯纤维的喷射混凝土相比,其弯曲韧性显著增强,界面黏结力大幅提升,抗压强度有所提高,聚丙烯纤维对混凝土扩展度、单轴抗压强度、弯曲韧性及氯离子扩散系数均产生积极作用,基于此,确定其最优掺量为0.9kg/m^(3)。速凝剂对喷射混凝土1d单轴抗压强度的提升效果显著,同时还能增强其抗氯离子渗透性能,综合速凝剂对混凝土扩展度、1d单轴抗压强度、氯离子扩散系数和电通量的作用,确定速凝剂最佳掺量为26kg/m^(3)。经配合比优化,喷射混凝土综合性能指标均符合铁路隧道施工应用要求。
In order to improve the comprehensive performance of shotcrete used in railway tunnel construction,the optimization of shotcrete mix proportion in railway tunnel construction was carried out through experiments.The performance of shotcrete was optimized by exploratory test,single factor test of polypropylene fiber content,single factor test of accelerator content and bending toughness test.The results show that polypropylene fiber mainly exerts secondary skeleton effect and strain energy absorption effect in shotcrete.Compared with shotcrete without polypropylene fiber,its flexural toughness is significantly enhanced,the interfacial adhesion is greatly improved,and the compressive strength is improved.Polypropylene fiber has a positive effect on concrete expansion,uniaxial compressive strength,flexural toughness and chloride ion diffusion coefficient.Based on this,the optimal dosage is determined to be 0.9kg/m^(3).The accelerator has a significant effect on the improvement of the 1d uniaxial compressive strength of shotcrete,and it can also enhance its resistance to chloride ion penetration.Considering the effect of accelerator on concrete expansion,1d uniaxial compressive strength,chloride ion diffusion coefficient and electric flux,the optimum dosage of accelerator is determined to be 26kg/m^(3).Through the optimization of mix proportion,the comprehensive performance indexes of shotcrete meet the requirements of railway tunnel construction.
作者
赵林
ZHAO Lin(China Railway 18th Bureau Group Third Engineering Co.,Ltd.,Zhuozhou,Hebei 072750,China)
出处
《施工技术(中英文)》
2025年第10期140-144,共5页
Construction Technology
关键词
隧道
铁路
喷射混凝土
配合比
聚丙烯纤维
试验
tunnels
railways
shotcrete
mix proportion
polypropylene fiber
tests
