MONITORING OF CLYDE AND ROXBURGH GRAVITY DAMS AND THEIR SCHIST FOUNDATIONS

摘要

Clyde dam, built in the 1980's, has an instrumentation system that was designed to be simple and reliable, with non-automated equipment. The dam safety philosophy is to promote visual observation as being equally important as instrumentation data. Data is collected by an experienced technician and evaluated by the owner's staff and reviewed by their dam safety consultants. The technician also completes a visual inspection report when visiting the instrument locations throughout the dam. The seepage, uplift and deformation monitoring at the dam were designed to monitor the general behaviour of the dam, and also to confirm lack of sliding or otherwise of foundation wedges bounded by faults and weak seams within the schist foundation. Roxburgh dam, built in the 1950's, did not incorporate an appropriate instrumentation system for measurement of dam and foundation deformations. The detailed knowledge of the foundation defects at Roxburgh dam was also not as extensive compared to Clyde dam. An instrumentation review was completed in parallel with a geological re-appraisal of the foundation conditions. This has lead to the installation of new instrumentation that allows the monitoring of the dam and foundation deformation, uplift within the dam foundation and all seepage flows. Such information significantly improves the dam safety management at Roxburgh dam.