Abstract: Initial stress is one of the important factors affecting the stability of geotechnical engineering. How to reasonably simulate the initial stress field is always an urgent problem in rock mass mechanics. Based on the 3-D stress measurements of a certain large-scale hydropower station construction site, the initial stress field of rock masses is analyzed by finite element method, The numerical model is established according to the topographical characters and real geometry of large structures and faults located at the site. The stress field at any point is thought to be composed of gravitational and tectonic stress components, while the gravitational stress component is assumed to be known as the results calculated by finite element method. When fitting the total tectonic stress component at the measurement points, unit normal displacement is applied to the model boundaries and the response is computed at the location of the measurement points in the model. In order to reproduce the measured stress at the measurement point, a linear regression expression is used to calculate the proportions of each unit response tensor. In addition, infinite element is also attempted to be introduced into the model of initial stress field analysis to meet the requirement of zeros displacement values on the boundaries; the preferable results obtained demonstrate that this method is powerful and feasible.

Key words: initial stress field, finite element, infinite element, numerical simulation