ABSTRACT
ABSTRACT: Lianghekou hydropower station locate in deep valley with slopes up to 500 m∼1000 m. The geo-stress measurement in range of PD12 foot-rill in the underground powerhouse show that the maximum principal stress value is about 21.57∼30.44 MPa, obvious peeling phenomenon is found on the cave wall of T3lh1(5) sandstone. The azimuth axis of the power house cavern must be chosen in consideration of both hydraulic characteristics of passageway and stability of surrounding rock. Three-dimensional nonlinear finite element analysis are carried out for both axis N3◦E and N7◦W respectively, then the comparison of the stress-strain, the stability of surrounding rock and supporting parameters in the two different axes are made. As the analysis shows, compared with N7◦W axis scheme, the N3◦E axis plan avoids stress release better, which significantly limits the deformation and the development of plastic zone. So the N3◦E solution is recommended.
