DEFORMATION AND MECHANICAL PROPERTIES OF THE LARGE UNDERGROUND CAVERN SURROUNDING ROCK WITH COMPLEX EXCAVATION

Complex geological condition and construction procedure are often met while constructing the big underground cavern,so study of stress and deformation of the surrounding rock can not only help us further understand the mechanical properties of rock mass,but also provide reference for support design and construction of big underground cavern.Deformation and stability of the underground cavern mainly focus on the crown of the chamber.Taking the underground power house of the Xiangjiaba hydropower station as an example,and introducing the three-dimension discrete element method(3DEC),the authors has studied the variations of displacement and stress under the complex excavation condition,compared the calculated data with the monitoring results,and proposed that the proper support distance is 5m delay the constructing face.