Analysis Of Initial Stress Field Regression And Excavating Abutment High Slope Using Three-dimensional Nonlinear Finite Element Method On Jinping

Jinping hydropower station is located on Yalong River in Sichuan province with installed capacity 3300 MW. The maximum height of the concrete parabolic double-curvature arch dam is 305.2 meters and it is the highest of the plans in the world. The study of initial stress field is of far-reach significance to the stability of both dam and the underground houses, at the same time, the stability of 300 meters high slope caused by the excavation of the foundation need further research.In combination with the geological data and the measured stress data of Jinping, using three-dimension (3-D) nonlinear finite element method (FEM), initial stress field, the stability of abutment high slopes and the reinforcement measurements of the project are systematically studied.First of all, integrated with the all data what was mentioned, built the 3D-model which can factually image the geological structure of Jinping, the regression estimation and the simulation technique are searched by regression step by step, and one of the two regression precepts which gains by contrast is to provide reasonable initial stress field for the following, the stability analysis of excavation of the high slop and surrounding rock of underground houses.As the initial stress field is determined, the excavation process of abutment is simulated with 3D-FEM, the load-off effect of rock slop and the distribution of stress, distance and the safe coefficient are studied, and then the conceivable failure parts and develop degree of rock are opened out. Based on these, corresponding reinforcement measurements are put forward and their reasonability and reliability are demonstrated.The features of this paper are: (1) according to the geological conditions of Jinping project, model is established fully considering the main faults, deep cracks and joint fissures that accord with actual conditions. (2) In the calculation of initial stress field, the maiden attempt that shear distance is introduced to adjust the direction of principal stress is entered for the simulation of tectonism, and the regression estimate is selected step by step, and then each character of two regression precepts is appraised by synthesis after the weight of the self-weight stress field in the initial geological stress field is discussed. (3) when the distribution of stress field, displacement field and failure information during each excavation process are studied, the nonlinear elastoplastic model named Drucker-Prager and the direct failure model in rock masses are considered in 3D-FME. (4) Through comprehensive analysis and demonstration, reinforcement measurements are put forward for the high slop and their working effectiveness is studied. (5) The sub-structure concerning implicit bolts is firstly used to research the bolts' strengthening function and their restrain for deformation.