A semihydrostatic model has been developed in order to assess the mechanical loads acting on heat-generating ILW (intermediate-level waste) and HTGR (high temperature gas-cooled reactor) fuel element waste packages to be emplaced in vertical boreholes according to the borehole technique. In this model, the borehole filling composed of emplaced packages and crushed salt is treated as a homogeneous medium with a density averaged according to the volume fractions, in order to derive the basic equations. The calculated pressure components depend both on the axial and the radial borehole coordinate.