高地温隧道衬砌混凝土早期开裂机理及防控措施  

Early Cracking Mechanism and Prevention Measures for Lining Concrete in High Geotemperature Tunnel

作　　者：傅金阳[1,2] 徐光阳 杨曾 赵宁宁 刘守花 FU Jinyang;XU Guangyang;YANG Zeng;ZHAO Ningning;LIU Shouhua(School of Civil Engineering,Central South University,Changsha 410075,China;National Engineering Research Center of High-speed Railway Construction Technology,Changsha 410075,China;First Engineering Co.,Ltd.,China Railway Fifth Bureau Group Co.,Ltd.,Changsha 410117,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中南大学高速铁路建造技术国家工程研究中心,湖南长沙410075 [3]中铁五局集团有限公司第一工程有限责任公司,湖南长沙410117

出　　处：《铁道学报》2022年第3期105-114,共10页Journal of the China Railway Society

基　　金：国家自然科学基金(52078496,U1934211);中南大学中央高校基本科研业务费(1053320192372);湖南省自然科学基金(2019JJ50747)。

摘　　要：为解决高地温隧道衬砌混凝土早龄期开裂问题,以我国西部某超高地温隧道为依托,利用理论推导、数值模拟与现场测试方法分析温度与湿度变化耦合作用下高地温隧道衬砌混凝土早期开裂机理及针对性保温隔热措施。研究结果表明:高地温与混凝土早龄期水化产热共同作用形成的温度应力是隧道衬砌早龄期开裂的内在原因,早龄期混凝土强度增长不足是表面开裂直接原因;高地温隧道诱发衬砌混凝土早龄期开裂的围岩温度临界值约为63℃,低于此值时隧道衬砌正常施工不会导致早龄期开裂;超过此围岩温度临界值时,建议在初支与二衬间设置夹心式保温隔热层,避免衬砌混凝土因过大内外温差出现早期表面开裂;采用夹心式保温隔热层相比二衬表面设置表贴式保温隔热层更具施工组织便利性,且可避免衬砌混凝土长期处于高温状态。研究结果可为高地温衬砌混凝土早龄期开裂风险防控和隔热措施设计提供参考。In order to solve the problem of early age cracking of tunnel lining concrete with high geotemperature,based on the ultra-high geotemperature railway tunnel in west China,the early age cracking mechanism of the lining concrete with high geotemperature under the coupling effect of temperature,humidity and corresponding thermal insulation measures were studied by using theoretical derivation,numerical simulation and field measurements.The results show that the temperature stress induced by the coupling influence of high geotemperature and hydration heat of early age concrete is the internal cause of the cracking of the tunnel lining in the early age,which leads to surface cracks when the increase in the strength of early age concrete is insufficient.The critical value of the surrounding rock temperature that induces early age cracking of the lining concrete is 63℃,below which the normal construction of the tunnel lining will not cause early age cracking.However,when the critical value of the surrounding rock temperature exceeds this value,it is recommended to set sandwich thermal insulation layer between the shotcrete layer and concrete lining to avoid early age surface cracking of the lining concrete due to excessive internal and external temperature difference.Compared with the surface-mounted thermal insulation layer on the surface of the secondary lining,the sandwich thermal insulation layer is more convenient for tunnel construction organization and can avoid the lining concrete from being in a long term high temperature state.The research results can provide reference for the prevention and control of early age cracking risk of lining concrete and the design of thermal insulation measures in high geotemperature area.

关 键 词：高地温 开裂机理 多场耦合 数值模拟 早龄期 开裂控制 

分 类 号：U25[交通运输工程—道路与铁道工程]