| Abstract: | A phototheodolite was used during the construction of Llyn Brianne dam to provide stereoscopic coverage of both upstream and downstream shoulders of the dam at each of eight stages of construction. Ground control was established on the valley sides, together with 80 targeted points at various levels on the dam as it progressed. The co-ordinates of the targeted points were determined numerically using a Wild A7. Three dimensional displacements were determined from the change of position to an average accuracy of 0–05 m. Agreement was obtained with independent and more precise measurements and comparisons are made with the upstream displacements. The assumptions of an analytical prediction technique are examined. Profile lines through the dam were also obtained numerically to record the progressing shape of the dam. |
