Research On The Initial Stress Field Around The Tunnels Of The Jinping Hydroelectic Peoject

The underground space technology is a development trend of Geotechnical engineering in the 21st century, and the initial stress in rocks and soils is an important parameter in the underground engineering design, therefore studying on the solution method of initial stress value is important.As to the tunnels of Jinping hydroelectric power station in Sicuan Province, the thesis discusses how to reasonably consider the initial stress field when designing a large-scale tunnel with high initial stress and deep buried .First, By analyzing of the rock lab tests and discusses the feature of regional geomorphology .explains the production of initial stress field , analyze the initial stress of Jinping hydroelectric power station ;second ,using the FEM, The paper creates the real model of region. According to the results of stress measurement point, by combining of ANN and FEM to decide the boundary condition ,the paper calculates the initial stress field; at last, the paper analyzes the influence of the initial stress field formed from different condition on the deformation and stress of the surrounding rock, and the main factor to influence the initial stress. On the basis of the former work, the author proposes some proposals, which will be helpful for studying and designing of the similar underground engineering.During analyzing the 3DNFEM, this thesis has used ANSYS to do finite element calculation for rocks and soils, to ANSYS finite element's parsing process and realizing method having done the acquirement, create and solve the real model basis on the ANSYS integral bullet plasticity model and nonlinearity equation resolution, and imitates the excavating problem using the "birth and death " of the element, and uses the sub modeling to carry on from the thick grid of large area domain to the dense grid of small region.