高地热环境隧道衬砌结构受力特征模型试验研究

Experimental Study on Stress Characteristics of Lining Structures of Tunnels in High Geo-temperature Environment

随着我国交通事业的发展,深埋高地热条件下的长大隧道越来越多。地热温度不仅对衬砌结构的受力特征有影响,而且会影响隧道结构的耐久性,但目前国内对高地热环境下隧道力学行为的研究有限。针对以上问题,以拟建的高地热环境下的高黎贡山隧道为工程背景,采用室内相似模型试验,通过逐步改变温度的方式,得到不同温度下隧道衬砌结构各部分受力特征和变化趋势:1)在地热温度作用下,隧道衬砌结构产生内力重分布,即在一定温度范围内,轴力基本随温度呈线性增长;弯矩总体上变化不明显,拱项部位弯矩随温度升高呈降低趋势,其他部分则呈相反变化趋势。2)衬砌结构的拱脚位置受温度影响最明显,应作为设计与施工时的重要控制部位。3)在温度荷载作用下,支护结构的整体安全储备(安全系数)明显降低。

Due to the development of transportation works in China,more and more deep tunnels are built in high geotemperature environment.Geo-temperature has influences on the stress characteristics and durability of the lining structure of tunnels.However,in China,few researches have been made on the mechanical behavior of deep tunnels in high geo-temperature environment.The stress characteristics and the stress variation tendency of different parts of the lining structure under different temperatures are studied by means of indoor model test,with Gaoligongshan tunnel as an example.Conclusions drawn are as follows：1） Internal force redistribution will emerge as the geothermal temperature creeps up; The axial force of the lining structure increases linearly as the temperature increases; Generally speaking,the bending moment of the lining structure does not change significantly,while the bending moment at the tunnel crown decreases as the temperature increases and the bending moment at other positions shows the opposite tendency; 2） The arch feet of the lining structure are seriously affected by the temperature,therefore much attention should be paid to the arch feet in the design and construction of the tunnel ; 3） Due to the effect of the temperature load,the safety margin （safety coefficient） of the lining structure is significantly reduced.These conclusions can provide reference for the design and construction of similar projects in future.