ABSTRACT
Stability analysis is a crucial task in the caverns excavation that depends on the site characteristics including geological and geomechanical parameters. In this study, geomechanical properties of rock masses, field stress and joints parameters of Rudbar Lorestan powerhouse cavern in Iran were investigated and displacements, as well as stresses, were evaluated using 3D numerical simulation and with considering Hoek-Brown criterion. This infrastructure has the main cavern with dimensions of 26.8 × 50 × 130.5 meters in width, height and length respectively. The stability of the cavern has been studied by investigating the side wall and crown deformation with and without a support system. Results show that installation of support system—including reinforced shotcrete lining of 35 cm, 10 meters grouted dowel and tendons—can reduce wall horizontal displacement and crown vertical displacement up to 65% and 75%, respectively. Therefore, the comprehensive method incorporating numerical analyses, as well as empirical study and filed observation has been proven to be very promising in deformation and even stability prediction of surrounding rock mass in underground caverns to delineate excavation damage zones.
