Numerical and Experimental Study on Propagation Attenuation of Leakage Vibration Acceleration Signal of the Buried Water Pipe

Abstract

For detecting water pipeline leakage signals, in the past people preferred to use sensors to obtain the leakage signal and then use various means and methods to remove noise to increase the positioning accuracy. However, as the leakage signal is generated, it spreads along the pipeline wrapped in soil. In this process, the signal will change significantly, eventually becoming very different from the original signal. As such, the detection accuracy will decline, as the detection distance becomes longer. Despite this, few researchers have considered the distortion caused by signal propagation in the whole process and instead use the distorted signal characteristics for positioning. This direction needs to be further studied. In this paper, the acceleration signal of leakage vibration is taken as the research object using a combination of tests and numerical simulation. The acceleration signals from the leakage source are collected and simulated at different distances. The reliability of the numerical simulation model is verified by using the inversion theory, and the influence of soil with different elastic modulus on the acceleration signal is expanded. Research findings: (a) For the attenuation of the acceleration signal of pipeline leakage vibration along the pipeline, the elastic modulus of soil around the pipeline in the numerical simulation model is about 3.3 times its compression modulus, which is closer to the actual situation. (b) The attenuation of the acceleration signal amplitude of pipeline leakage vibration conforms to the characteristics of an exponential function. The higher the elastic modulus of soil, the stronger the signal attenuation. (c) The soil with different elastic modulus has different absorption capacities to signal components, and the high-frequency part of the acceleration signal attenuates faster. (d) The group velocity of the leakage vibration signal is 929 m/s, and the different elastic modulus of soil will affect the group velocity of the leakage vibration signal.