水工隧洞混凝土施工期气温演变规律监测分析

Monitoring and Analysis of Temperature Evolution in Hydraulic Tunnel During Construction of Concrete

洞内气温是水工隧洞衬砌混凝土温度裂缝控制最为重要的环境条件之一,由于缺乏足够的实测资料和研究成果,至今还没有掌握其演变规律,设计和温控计算中取值差异显著。通过对白鹤滩等巨型水电站中不同用途数十条隧洞混凝土浇筑期洞内气温10余年监测,取得万余组数据。认识到水工隧洞沿河布置与河套风向一致,洞口开挖贯通,交通洞和施工支洞众多,洞内温度主要受自然环境气温控制。通过统计分析,提出洞内气温采用余弦函数描述其年演变规律,年平均值和变幅与隧洞长度、开挖是否贯通、地下电站施工热源、封闭洞口保温等4要素的定量关系,可供没有隧洞气温检测数据时计算洞内温度参考。

The temperature in the tunnel is one of the most important environment conditions for temperature control and crack prevention of lining concrete.Due to the lack of sufficient research data,its evolution law has not been mastered so far.At Xiluodu,Baihetan and other giant hydropower stations,the temperature in dozens of tunnels during concrete construction has been monitored for more than 10 years,and more than 10000 groups of data have been obtained.It is recognized that the tunnel layout along the river direction is consistent with the wind direction of the river oxbow.During the construction period of lining concrete,there exist many access tunnels and adits,and the temperature in the tunnel is basically controlled by the ambient temperature.Through statistical analysis,the cosine function can be used to describe its annual evolution rule.The average value and amplitude of annual variation of temperature in the tunnel have quantitative relationship to the layout of tunnel,excavation condition,portal state,etc,which can be used as a reference for calculating the temperature in the tunnel without detection data.