高地温隧洞支护结构受力特性

Mechanical characteristics of supporting structures for high geo-temperature tunnel

高地温问题严重制约了地下工程的施工和安全运营,结合新疆某水电站引水洞存在的高岩温问题展开研究。根据地质资料设置了6种地温边界,研究隧洞围岩及支护结构在开挖、施做喷层、施做衬砌和过水等工况下的受力及变形特性,并与不考虑温度场时的分析结果进行了对比分析。研究表明:高温对隧洞稳定性有显著的影响,高温下锚杆轴力约为不考虑温度场时的294倍,衬砌环向拉应力约为不考虑温度影响时的2.13倍;保温层作用显著,若不考虑保温层的影响,锚杆轴力和衬砌拉应力会更大;过水对衬砌受力影响较大,过水后衬砌环向拉应力迅速增大为过水前的2.65倍。研究结果为类似工程的设计与施工提供借鉴。

High geo-temperature is a serious constraint to the construction and safe operation of underground engineering,will be studied based on a diversion tunnel in Xinjiang.According to the geological data,six different temperature boundaries were chosen.The deformation and stress characteristics of the surrounding rock and supporting structures were studied under four operating conditions such as spraying shotcrete,pouring concrete and flowing water.The research shows that the high geo-temperature has a marked impact on tunnel’s stability,the axial force of bolt was 294 times as those which did not consider temperature,while the circumferential tensile stress was about 2.13 times;the insulating layer worked dramatically well,the axial force of bolt and circumferential tensile stress of lining were bigger if without insulating layer;the cold water had big impact on the lining stress,circumferential tensile stress of lining was 2.65 times as that without water flowing.The research results provide reference for the design and construction of similar project.