Methodology of Displacement Detection for Water Supply Pipeline by IMU Sensors

摘要

The mechanical behavior of underground buried objects such as water supply pipelines is relatively difficult to be measured and analyzed from the ground. The displacement of the pipe might be caused by ground deformation, leakage or other damage, etc. The displacement is accompanied by a change in the angle of the pipe at the point of connection. In this study, the bending test was carried out using an IMU (Inertial Measurement Unit) sensor to measure the angular displacement of the water pipe. A MEMS-based triaxial acceleration sensor was used for the IMU sensor. The bending test was carried out to determine the threshold value at the time of breakage of the pipe and vertical pressure was applied to the connection point of the DCIP (Ductile Cast Iron Pipe) and PVC (Poly Vinyl Chloride) pipes. Upon the threshold at breakage, it was found that the pipe was seriously damaged when the angle of the DCIP and the PVC reached to 7.7 and 12.7 degrees, respectively. It was denoted that the DCIP is more sensitive than the PVC when displacement occurs due to direct damage of the water supply pipe or ground deformation. In case of the DCIP, when the strength is superior to that of the PVC pipe but an external force such as the ground deformation of the ground acts, it is judged that the functionality of the water supply pipe can be remarkably reduced even if the displacement is small. Therefore, it is concluded that it is necessary to convert the influence of the change of the threshold value and the ground deformation at the time of failure according to the characteristics of the pipe to DB. From this point, it is noted that the IMU sensor of this study can be used to evaluate the structural diagnosis of the pipe and the risk of the ground collapse due to the ground deformation at low cost.