AbstractThe plate loading test is performed in order to determine the deformation modulus of a rock massin situ.In the standard execution of this test the loading is applied perpendicular to the rock surface. The displacements are measured on the axis of symmetry, since for an isotropic material with linear deformation characteristics exact formulae are known which are valid at this location. For horizontal strata this presents no problem as it is easy to provide loading in a vertical direction. When the rock strata are dipping it is imprectical to use nonvertical load and it is then necessary to calculate the modulus from the displacements in a non‐axisymmetrical arrangement. Using the well‐known method of the Taylor series approximate formulae are derved which are sufficiently accurate for all practical cases of sloping r