The expression of strength margin safety factor of Drucker-Prager yield criterion was deduced. Taking construction of surge shaft large-scale underground cavern group of Nuozhadu hydropower station for example, the influence from excavation of surge shaft large-scale underground cavern group on the stability of surrounding rock was studied through the displacement, minor principal stress, and safety factor of key point during the process of excavation. The results show that the strength margin safety factor decreases with the increase of the difference of principal stresses. The stability of s...
