抽水蓄能电站管道水力振动在围岩中的传播规律研究

Propagation law of hydraulic vibration of pipelines in surrounding rock of pumped storage power station

针对抽水蓄能电站运行引发的场地振动问题,以某抽水蓄能电站为例,建立“水力荷载-管道-围岩”有限元-无限元耦合模型,研究抽水蓄能电站管道水力振动在围岩中的传播规律,为减振提供技术支撑。首先基于水力振动理论、传递矩阵法和水力阻抗法建立抽水蓄能电站管道水力脉动荷载计算方法;然后采用耦合模型系统分析了弹性模量、阻尼、机组运行状态等变化对管道水力振动在围岩中传播的影响,并给出减振措施。计算结果表明:随着岩石弹性模量的增大,管道水力振动在围岩中衰减速率变慢,由管道水力振动引起的场地振动增大。当围岩阻尼比从0.02增大到0.30时,管道水力振动引起地表的振动强度不断减小。阻尼比从0.02增加到0.10时,地表振动强度衰减了85%~97%;阻尼比从0.20增大到0.30时,地表振动强度衰减了0.1%~1.0%,变化比较平缓。对于该抽水蓄能电站,当运行更多机组时,引发的地表振动更大,且该电站在抽水运行时较发电运行时引发的场地振动强度更大。

In order to investigate the ground vibration caused by the operation of pumped storage power stations,taking a pumped storage power station as an example,we established a finite element-infinite element coupling model of“hydraulic load-pipe-surrounding rock”to study the propagation law of hydraulic vibration of the pipeline in the surrounding rock,so as to provide some technical support for the vibration reduction.Firstly,based on hydraulic vibration theory,transfer matrix method and hydraulic impedance method,the method for calculating the hydraulic fluctuating load of the pumped storage power station pipeline is established.Then,the coupling model is used to systematically analyze the influence of the changes of elastic modulus,damping and unit operating state on the propagation of hydraulic vibration of pipeline in the surrounding rock,and the damping measures are proposed.The calculation results show that with the increase of the elastic modulus of rock,the attenuation rate of hydraulic vibration of pipeline in the surrounding rock decreased and the ground vibration caused by hydraulic vibration of pipeline increased.When the damping ratio of the surrounding rock increased in the range of 0.02 to 0.30,the intensity of the surface vibration caused by the hydraulic vibration of pipeline kept decreasing.When the damping ratio increased from 0.02 to 0.10,the surface vibration intensity decreased by 85%-97%;when the damping ratio increased from 0.20 to 0.30,the surface vibration intensity decreased only by 0.1%to 1.0%,which changed relatively little.For this pumped storage power station,when more units are in operation,the resulting ground vibration is greater and the ground vibration intensity during pumping operation is greater than that during power generation operation.