高地温隧洞温度场数值模拟研究

以新疆某水电站高地温引水发电隧洞为依托,对高地温段引水发电隧洞在有无EPS保温隔热层下的温度场分布进行模拟研究。结果表明,距离隧洞中心越远,在有、无EPS保温隔热层条件下隧洞的温度均越高;EPS保温隔热材料厚度依次取3、5、10cm时,隧洞衬砌支护结构温度梯度明显降低,且在EPS保温隔热层处温度发生突变,突变处温度幅值依次为20.6174、26.7323、39.3442℃;EPS保温隔热层越厚,衬砌支护结构温度梯度越小,与现场实测结果极为吻合。鉴于此,在高地温引水隧洞施工过程中,可在二次衬砌前施做保温隔热层,用于阻断来自围岩深处的高温,从而降低衬砌支护结构与洞内环境温度的温差,减小二次衬砌结构所受到的温度应力,为高地温引水隧洞降温措施的设计与施工提供理论依据。

NUMERICAL SIMULATION OF THE INFLUENCE OF EPS HEAT INSULATION LAYER ON TEMPERATURE FIELD OF HIGH TEMPERATURE WATER DIVERSION POWER TUNNEL

The problem of the high temperature of water diversion power tunnel not only affects the construction schedule and investment of the water conservancy project construction,but also determines the feasible plan of the project,especially in the abnormal high geothermal areas.Based on the high geothermal water diversion power tunnel of a hydropower station in Xinjiang,the temperature field distribution was simulated under the EPS heat insulation layer existed or not.The results show that the farther distance from tunnel center,the higher of temperature without EPS heat insulation layer or having.When the thickness of EPS heat insulation material was 3cm,5cm or 10cm,the temperature gradient of the supporting structure of the tunnel significantly reduced,and the temperature at the EPS heat insulation layer was found about 20.6174、26.7323、39.3442℃ temperature mutation in turn.The thicker the EPS heat insulation layer is,the smaller the temperature gradient of the supporting structureis,which was in good agreement with the field test results.In view of this,during the construction process of the high temperature water diversion tunnel,the heat insulation layer should be built before the secondary lining.The heat insulation layer could be used to block high temperature from the depths of the surrounding rock and reduced the temperature difference between the lining structure and environmental temperature.Therefore,temperature stress applied to the secondary hning structure was reduced,which will provide a theoretical basis for the design and construction of the cooling measures of high temperature water diversion power tunnel.