A method for leak detection in buried pipelines based on soil heat and moisture

Abstract

Leakages in urban heating pipeline networks are mostly caused by underground corrosion, external environment interference and construction. The fluid leaking from pipes accumulates in surrounding soil for a long time, resulting in changes in soil machinery and hydraulic structure, and potential accidents threaten people's daily life and property safety. A preliminary judgment was made to determine whether the pipeline failed according to the infrared images of underground heating pipeline taken from the actual engineering. By comparing the soil moisture around the faulty pipe, we subsequently proposed a fault detection method for buried pipelines which coupled infrared thermography and the variation characteristics of surrounding soil moisture. In order to verify the effectiveness of this method, the numerical simulation was carried out on a leaking buried pipe, and the variation characteristics of soil heat and moisture in the direction of the failure point and its driving mechanism were analyzed. The results showed that the difference between the internal and external pressures at the failure point of the leaking buried pipeline enhanced the effect of soil pressure potential, resulting in significant heat and moisture transfer in soil, which contributed to detecting the buried pipeline failure and identifying the failure types of buried pipelines.