地下压气储能圆形内衬洞室内压和温度引起应力计算

Analytical approach for stress induced by internal pressure and temperature of underground compressed air energy storage in a circular lined rock cavern

地下压气储能岩石内衬洞室内,不断变化的气体内压和温度引起的应力场是关乎洞室稳定性、耐久性的重要因素,由此提出了一种计算气压和温度引起应力变化的解析方法。将内衬洞室考虑成由密封层、衬砌和围岩组成,首先建立了洞室温度和气压求解的控制方程;利用拉普拉斯变换和叠加原理得到每个循环内洞室温度和气压随时间的变化;采用热弹性模型得到内压和温度引起的应力场。基于解析方法,给出了典型循环周期内洞室应力变化情况;接着通过一个热–力以及洞室气体耦合求解的数值模型以及不考虑密封层和衬砌的温度场解析方法来验证本文方法;最终探讨了温度对总应力的影响程度,以及不同换热系数的影响。结果表明:本文方法是可行的;温度和内压引起的密封层和衬砌内环向拉应力非常大;温度对于压气储能洞室有着不可忽略的作用,温度对于环向和纵向应力的影响程度要大于对径向应力的影响;换热系数对应力变化影响很大。

As the stress induced by varying temperature and air pressure is important for the stability and durability of underground compressed air energy storage in lined rock caverns, an analytical approach for the induced stress is proposed. The cavern with a sealing layer, concrete lining and host rock is considered, the governing equations for temperature and air pressure of the cavern are established. The temperature field and air pressure during the operation period are obtained using the Laplace transform and the principle of superposition. Then the induced stress variations are determined analytically by employing a thermo-elastic model. The stress induced during a typical operation cycle is illustrated. The approach is subsequently verified by a coupled compressed-air and thermo-mechanical numerical simulation and by a previous study for temperature. Finally, the influence of temperature on the total stress and the impact of heat transfer coefficient are discussed. The results reveal that the caused tensile hoop stresses in the sealing layer and concrete lining are quite large. Moreover, the temperature has a non-negligible effect on the lined cavern for underground compressed air storage, while the hoop and longitudinal stresses are affected by the temperature to a larger extent than the radial stress. In addition, the heat transfer coefficient affects the cavern stress to a high degree.