Based on the elastic theory of orthotropic material
the 2-D and 3-D constitutive equations are obtained in off-axes coordinate system. The stress distribution near the borehole is amended by applying stress calculus of variation
and in addition
the equation for calculating radial displacement of wall of borehole is gotten. With the character of borehole radial deformation in ground stress measurement
a method is put forward for measuring the geostatic stress of orthotropic rockmass. It is verified in a practical project comparing with the conventional isotropic method