Determining the Subsidence of Oil Storage Tank Walls from Geodetic Leveling

摘要

In this paper the monitoring for subsidence in crude oil storage tanks by the method of Geodetic leveling is discussed. The monitoring network consisted of three control points established about 100m from the tank and 16 studs established at the base of the tank. From the control points, the stud locations were leveled using a geodetic level with parallel plate micrometer and telescopic staves. All levels were run in forward and reverse directions and the measurements were carried out in 2003, 2004 and 2008. Adjustment of observation was carried out using the least squares estimation model to determine the elevation of each stud position in the three measurement epochs together with their accuracy standards. Comparisons were made of the calculated movements from the three measurement epochs and the associated accuracies calculated from the least squares model. Analysis of the results indicated that with the exception of one stud (stud 8), all other studs emplaced had moved and the movements ranged from 0.91mm to 13.06mm.