不同龄期隧道喷射混凝土渗流结晶规律研究  

Study on Seepage Crystallization Pattern of Tunnel Shotcrete of Different Ages

作　　者：同月苹 田崇明 叶飞[1] 姜寅 张俊元 伍博文 王涵 李文辉 TONG Yueping;TIAN Chongming;YE Fei;JIANG Yin;ZHANG Junyuan;WU Bowen;WANG Han;LI Wenhui(School of Highway,Chang′an University,Xi′an 710064;YCIC Investment Co.,Ltd.,Kunming 650103)

机构地区：[1]长安大学公路学院,西安710064 [2]云南交投集团投资有限公司,昆明650103

出　　处：《现代隧道技术》2024年第1期272-282,共11页Modern Tunnelling Technology

基　　金：云南省交通运输厅科技创新示范项目(云交科教便[2019]59号);中央高校基本科研业务费专项资金—长安大学优秀博士学位论文培育资助项目(300102212706).

摘　　要：隧道排水系统结晶堵塞病害与地下水在喷射混凝土中的渗流密切相关。为了探究喷射混凝土养护龄期与结晶病害的关联性,采用自制室内模型装置模拟隧道喷射混凝土渗流-结晶全过程,通过测定结晶体质量、排水管流出溶液pH值及钙离子浓度,综合XRD、热重分析、扫描电镜和压汞测试等方法,揭示地下水渗流条件下不同龄期喷射混凝土劣化发展及排水管内结晶规律。结果表明:(1)喷射混凝土养护龄期是影响隧道结晶病害的关键因素,早龄期的影响尤为显著,2 h龄期混凝土在渗流条件下排水管内结晶量基本达到28 d混凝土的30倍;(2)混凝土养护龄期越长,pH值下降速度越快,pH值稳定时间越早,钙离子浓度稳定时间越早;(3)不同龄期混凝土内部渗流60 d后,混凝土内部仅观察到极少量钙矾石和C-S-H凝胶产物,结构分布不均匀,且总孔隙率大;混凝土内部均有氢氧化钙晶体分布,随着养护龄期增长,由少量毛絮状不稳定状态转变为大量片状—块状的较稳定状态;养护龄期越长,混凝土水化产物溶出越少;热重分析表明,28 d龄期混凝土内氢氧化钙含量是2 h龄期混凝土的5.9倍。The crystallization induced blockage defect in tunnel drainage system is closely related to groundwater seepage in shotcrete.In order to ascertain the correlation between the curing age of shotcrete and crystallization in⁃duced defect,a home-built indoor simulation device is used to simulate the seepage-crystallization process of tun⁃nel shotcrete.The mass of crystal and the pH value and calcium ion concentration of effluent solution from drainage pipe have been measured,and XRD,thermogravimetric analysis,electron microscope scanning and mercury injec⁃tion test have been conducted,so as to reveal the deterioration process of the shotcrete of different ages and the crys⁃tallization pattern in drainage pipe under groundwater seepage conditions.As the results indicate:(1)The curing age of shotcrete is a key factor that affects the crystallization induced defect of tunnel,and the early age affects it particu⁃larly significantly.Under seepage conditions,the crystal mass in drainage pipe in the concrete with 2 h age is essen⁃tially 30 times that in the concrete with 28 d age;(2)Longer concrete curing age means the pH value will decrease faster,pH value will stabilize sooner and calcium ion concentration will stabilize sooner;(3)After 60 d of internal seepage in the concrete of different ages,only very small amount of ettringite and C-S-H gel are observed inside the concrete,the structure is uneven,and the concrete has high total porosity;The interior of concrete contains calcium hydroxide crystal,and as the curing age increases,the crystal changes from small amount of flocculent crystal in un⁃stable state to large amount of lumpy crystal in stable state;Longer curing age means less concrete hydration products are dissolved out.According to the thermogravimetric analysis,the calcium hydroxide content of the concrete with 28 d age is 5.9 times that of the concrete with 2 h age.

关 键 词：隧道 排水管结晶堵塞 喷射混凝土 养护龄期 渗流结晶 

分 类 号：U456[建筑科学—桥梁与隧道工程]