摘要
针对川西高海拔隧道抗防冻设计问题,对运营期公路隧道洞内气温采用实测和数值模拟等方法,对隧道洞内纵向温度特征及抗防冻设计方法进行研究。结果表明:1)川西高原较短隧道冬季洞内纵向温度呈负温贯通状态,长隧道、特长隧道的洞内纵向温度呈现出弱对称或非对称分布特征。2)冬季隧道洞口温度及洞身负温分布状态与隧道自身所处环境有关,尤其是隧道两端地形特征及高差程度。3)洞口负温段冻结指数和年冻结天数均随进洞距离的增大呈减小趋势,但单向自然风占主导的隧道下降趋势较缓。4)川西高原隧道衬砌防冻设计宜结合围岩冻胀敏感性,考虑以冻结指数180℃·d为临界值较为合理,两侧水沟保温设防长度可按月平均气温0℃考虑;考虑到冻结指数大于180℃·d且月平均气温低于0℃的衬砌段落会经受短时频繁冻融循环作用的影响,建议采取必要措施改善混凝土耐久性指标,确保隧道衬砌结构的长期稳定性。
The authors investigate the longitudinal temperature characteristics and anti-freezing design methods for a highway tunnel in the western Sichuan plateau,China,through field temperature measurements and numerical simulations conducted during the operational period.The findings are as follows:(1)The longitudinal temperature in short tunnels in the western Sichuan plateau shows negative temperature penetration in winter,while long and extra-long tunnels exhibit weakly symmetric and asymmetric temperature distributions.(2)The temperature distribution at the tunnel portal and the occurrence of negative temperatures inside the tunnel are influenced by the surrounding environment in winter,particularly the terrain features and the height differences at both tunnel ends.(3)The freezing index and the annual number of freezing days at the tunnel portal decrease with increasing distance from the portal.This decrease is slower in tunnels where one-way natural wind prevails.(4)The antifreezing design of tunnel lining structures in the western Sichuan plateau should be based on the frost-heave sensitivity of the surrounding rock.A freezing index of 180℃·d is recommended as the critical value.The insulation length for the ditches on both sides of the tunnel can be determined by the monthly average zero-degree temperature.For lining sections with a freezing index exceeding 180℃·d and a monthly average temperature below 0℃,short-term freeze-thaw cycles frequently occur.Thus,the concrete durability index should be enhanced to ensure the long-term stability of the tunnel lining structure.
作者
郑波
吴剑
袁明
郑金龙
郭瑞
ZHENG Bo;WU Jian;YUAN Ming;ZHENG Jinlong;GUO Rui(China Railway Southwest Research Institute Co.,Ltd.,Chengdu 611731,Sichuan,China;China Railway Investment Group Co.,Ltd.,Beijing 100055,China;Sichuan Highway Planning,Survey,Design and Research Institute Ltd.,Chengdu 610041,Sichuan,China)
出处
《隧道建设（中英文）》
CSCD
北大核心
2024年第9期1771-1782,共12页
Tunnel Construction
基金
四川省自然科学基金项目(2024NSFSC0158)
中国中铁股份有限公司科技开发计划项目(2021-重大-19)
中国国家铁路局集团有限公司科技研究开发计划项目(N2021G057)。
关键词
高海拔隧道
纵向温度场
抗防冻设计
现场监测
数值模拟
冻结指数
冻结深度
high-altitude tunnel
longitudinal temperature field
anti-freezing design
on-site monitoring
numerical simulation
freezing index
freezing depth
