Stability analysis and selection of optimuim support system of large scale underground space-Case study

The Azad pumped storage power plant including the pumping and transformer cavern and surge tanks has been located in the Sanandaj-Sirjan formation with the alternation of slate and phyllite and meta sandstone.Due to the sensitivity and special use of these spaces, stability analysis and ensuring the safety of carven is very important.Nowadays, using the surface storage tanks is very costly; Therefore, the use of underground cavernsin large volumeseven in weak rock mass, is more economical than surface reservoirs. Totally, we can classify the main applicable caverns in five groups, including the hydropower plants and pumped storage, liquid storage, storage of nuclear waste disposal, waste water and sewage systems and alsomiscellaneous applications. The aim of studying Pumped Powerhouse - open-damstorage project isexploring the possibility of establishing Pumped - storage powerhouse systems inopen range of reservoir dam and assessing the potential of hydroelectric energy generation in this system