The Application of the Least Square Method in Back Analysis of 3D Initial Geostress

According to in situ measurement, the simplified geological model is established and calculated by FLAC^3D. Then, a multivariate regression model is built between the measured and calculated results of geostress at measured points. Based on the measured geostress, the regression analysis is carried out by the least square method. Through multiple regression analysis, the optimal regression coefficient can be derived. By comparing the influence on initial geostress field of taking account of fault and taking no account of fault, the distribution tendency of initial geostress field can be obtained. The geostress regression analysis results indicate that the calculated results are in a good agreement with the in situ measured data and can be used to engineering practice.