سال انتشار: ۱۳۹۰
محل انتشار: اولین کنفرانس بین المللی و سومین کنفرانس ملی سد و نیروگاههای برق آبی
تعداد صفحات: ۱۱
Reza Jamshidi Chenari – Dept of Civil Engineering, Guilan University, Rasht,Iran
Mohammad Hadi Sadaghiani – Deptof Civil Engineering, Sharif University of Technology, Tehran, Iran
Underground hydropower projects consist of complex underground spaces. Usually the powerhouse caverns are the largest and the most complex part of these spaces.The excavation and supporting sequences of these caverns are crucial from technical, construction and economical point of view. It is necessary to control the stability ofthese spaces and analyze displacements and stress distribution as the excavation proceeds. Large underground caverns of Karun 3 Dam and hydro project werestudied in this research. Karun 3 project is one of the major hydro projects in Iran.The geology of the dam site includes Asmari and Pabdeh formations, consisting of limestone and marly limestone. There are five instrumentation stations along thehydropower cavern. Instruments were multiple point borehole extensometers (MPBX) and load cells. A two dimensional distinct element modeling was used for theseanalyses. The powerhouse cavern, the transformer cavern and the inlet valve gallery were modeled along with the major discontinuities. Six patterns of excavationsequences were selected to be analyzed. These patterns consist of 6-, 14- and 18-partexcavation sequences with variable width of excavated spaces. The results of the stability analyses show that a pattern with 18-part excavation sequences has thelowest displacement values around the excavation, thus causing the most stable condition. Considering the ease of construction, the model with lower number ofexcavated parts is preferred. Therefore, the pattern with 14-part excavation sequences which also has low displacement values around the excavation was chosen as theoptimum pattern for construction.