Abstract：Based on the measured data of geostress and engineering-geological conditions in the region of the left bank high slope at Longtan hydropower station，possible factors affecting the initial geostress field are discussed. Under individual effect of factors，the established 3D simplified geological model of the left bank high slope is calculated by FLAC3D. Then，a multivariate regression model is established between the actually measured and corresponding calculated results of geostresses. Through multiple regression analysis，the optimum regression coefficient can be derived. Through the comparison between computed and measured geostress values of measuring points，it has been found that the two are similar in values and directions，which suggests the accuracy and reasonability of the geostress field regression. Thereby，the distribution tendency of initial geostress field of left bank high slope region can be obtained，providing a rational 3D initial geostress field for excavating simulation and analysis of long-term stability of the left bank high slope at Longtan hydropower station.
