Abstract：To study the relation between stresses and rock burst during tunnel excavation at Jinping Ⅱ hydro-power station，3D in-situ stress measurements are carried out by hydraulic fracturing and over-coring from 130 m to 3 005 m along tunnel. The measured results are as following：(1) in-situ stress at shallow depth of tunnel is controlled by dead weight topography and region formation，and a typical stress distribution of “V” shape for river valley is formed. The maximum stress is about 11.0 MPa with the direction NNW. The in-situ stress at deep depth of tunnel is high with the maximum stress about 40 MPa，and the direction is about closely vertical；(2) the direction of maximum stress changes from level state to vertical state along with increasing of level burying，indicating that dead weight stress is the dominant effect；and (3) the maximum compression stress and minimum compression stress within the tunnel cross-section are obtained by stress analysis. The possibility of rock burst is analyzed with rock burst criterion. The rock bursts are controlled by different stresses within the tunnel cross-section and restrained by ground water growth.
