Abstract：The initial geostress field of tunnel area is analyzed by 3D multivariate FE regression based on limited points of in-situ geostress measurement. Two large-scale 3D FE computational models are established. Then geostress including gravity，tectonic stress field for horizontal extrusion and shear in four cases are computed by with ANSYS. And the multivariate regression analysis is carried out by MEBA and MEBAC，which is an interface program connecting MEBA and ANSYS. It is emphasized on the analysis of complicated stress condition and macro description of stress field around Wushaoling tunnel，especially the stress condition in and around the faults F4，F5，F6 and F7. The results of macro geostress field indicate that the direction of principle stresses is N21.2°E，which forms separation angle of 38.2° to the tunnel axis. The tunnel lining in faults zone is extruded in longitudinal direction and stressed asymmetrically in horizontal direction. The values of the geostress are relatively large. The maximal vertical geostress is 32.10 MPa and the maximal geostress perpendicular to tunnel axis is 21.72 MPa. The results of macro geostress field are very important for dynamic design and construction.
