埋地管道漏损检测的声传播特性研究

地下管道漏损的准确定位问题一直是困扰世界范围内供水系统和市政建设的难题。管道漏损不仅会浪费大量的资源，而且还会造成严重的事故以及环境污染。针对埋地管道这样一个典型的土-管-液三相耦合问题，将管道周围土壤做弹性体考虑，对弹性介质中充液管道的声传播特性进行了解析研究。推导了低频域周向波数n=0的轴对称管道振动耦合方程，通过数值方法分别得到了流体波(s=1)和壳体压缩波(s=2)的复波数解。结果显示，管外土介质会使管道流体波波数减少(也即加快波的传播速度)，而对壳体压缩波的传播影响较小。由于管-土作用产生的能量辐射，在整个研究频段s=1波和s=2波都有较大的衰减。研究结果可为埋地管道漏损的精确检测提供理论支持。

Characteristics of sound propagation in a buried pipe for leak detection

The buried pipe for leak detection is a typically coupled system including three phases,i.e.,soil,pipe and fluid.With the surrounding soil treated as elastic medium,characteristics of sound propagation were studied analytically for a fluid-filled pipe surrounded by elastic medium.Coupled vibration equations of pipe for n=0 axisymmetric wave motion were derived,and complex wavenumber solutions were obtained by numerical method for both s=1 wave and s=2 wave,which correspond to a predominantly fluid-borne wave and a compressional wave in the shell,respectively.The results show that the wavenumber of fluid-borne wave will decrease while nearly no effect emerges on compressional wave due to the existing of surrounding soil.Since the coupling between the pipe and the soil will result in energy radiation,larger attenuation arises for both s=1 wave and s=2 wave.The conclusion will give some help for leak detection of buried pipes.