高地温引水隧洞支护结构的受力特性分析

Analysis of mechanical characteristics for high geothermal water diversion tunnel supporting structure

为了研究新疆某水电站高地温引水隧洞支护结构的受力特性,利用实测温度数据,结合弹性力学的拉梅公式计算与分析了隧洞衬砌施工期、运行期和检修期3种工况下4种计算情形下的径向应力、环向应力和轴向应力。计算分析结果表明,运行期由于过水内外壁温差较大,拉应力值大于施工期和检修期的拉应力值,其中拉应力主要是温度拉应力;3种工况下弹性模量随着温度变化比衬砌参数不变情况下的衬砌径向最大应力大0.02-0.04 MPa左右,比衬砌环向最大拉压应力大0.2 MPa左右,比衬砌轴向最大拉压应力大0.05 MPa左右;线膨胀系数随着温度变化引起的衬砌应力变化可忽略不计。上述结果可为高温引水隧洞衬砌设计提供依据,对类似工程设计有一定的参考价值。

In order to study mechanical characteristics for supporting structure of high-temperature diversion tunnel of the hydropower station in Xinjiang,this paper used the actual temperature data and combined with knowledge of elastic mechanics, analyzing of tunnel lining during construction, operation and maintenance of the three conditions of four cases of radial stress, hoop stress and axial stress. Results from the study, because of the water resulted large temperature difference between the inside and outside during operating period, the value of tensile stress which is mainly temperature tensile stress in the operation period was apparently higher than that in the construction period and the maintenance period. Under the three conditions, the maximum stress of the lining of the elastic modulus with the temperature change is larger than that of the lining under the condition of constant lining parameters about 0.02-0.04 MPa. The maximum tensile stress and the maximum compressive stress of the lining under the elastic modulus with the temperature change is larger than that of the lining under the condition of constant lining parameters about 0.2 MPa. Axial maximum tensile stress and maximum compressive stress of lining under the elastic modulus with the temperature change is larger than that of the lining under the condition of constant lining parameters about 0.05 MPa. Lining stress change due to thermal expand coefficient with the temperature change can be negligible. This paper provides a strong basis for the design of high temperature water diversion tunnel lining and hopes to have a certain reference value for similar engineering design.