سال انتشار: ۱۳۹۰
محل انتشار: اولین کنفرانس بین المللی و سومین کنفرانس ملی سد و نیروگاههای برق آبی
تعداد صفحات: ۱
Anton Schleiss – LCH-EPFL, Switzerland
The use of high strength steels for pressure shafts and tunnel liners and taking into account significant rock mass participation allows designing rather thin steel liners in hydropower projects. Nevertheless during emptying of the waterways these steel linings may be endangered by buckling. Compared to traditional measures as increased steel liner thickness and stiffeners, pressure relief valves are a very economical solution for the protection of steel liners against critical external pressureand therefore buckling during emptying. For the design of the required number and the arrangement of the pressure relief valves, a calculation procedure has beendeveloped and used successfully in practice. With recent systematic model tests, theassumptions of the design method could be verified. A new monitoring procedure for detecting the local drop of wall stiffness of steel-linedpressure tunnels and shafts is presented. It uses the water hammer pressure records to identify the presence of the weak reach and to extract its location and severity. Thismonitoring method is based on the theoretical approach of water wave reflections induced by the pressurized water reaches with different hydro-acoustic parameters. Ithas been validated by a series of experimental tests that have been carried out on aphysical scaled facility. The assessment of in-situ pressure data that are measured at the shaft of a pumped-storage power plant are now in process to test and extend themonitoring method to real scale structures.