Abstract:

 Insitu geostress field is one of the most important factors in geotechnical designs and constructions. On basis of the insitu geostress measurement results and the fact that the hydraulic fracturing test does not incur vertical shearing forces, the insitu stress field of the calculation area can be obtained by means of 3D finite element regressive analysis method and multivariate regression analysis principle, with the assumption that the gravity stress and structural stress of the rock mass are components of the stress field. The described 3D FEM regressive analysis method is applied for the section from Niqu to Duke river on the west route of SouthtoNorth Water transfer Project of China, which demonstrates that the calculated results are in good agreement with the insitu measured data and that the described method is feasible and easily understood.