A method for making a block for geotechnical applications, the block comprising a composite body including a section of a used wind turbine blade comprising a part of the used wind turbine blade leading edge, trailing edge and the windward surface and leeward surface, wherein the body is configured to be open from above and below, and fragments of the windward surface, leeward surface, leading edge and trailing edge of the used blade comprise the body side walls, and wherein an inside of the body is filled with a filling material, the method comprising the steps of:
- marking a section on a used wind turbine blade, between its tip and root for mounting in a hub,
- cutting out within this section the block body in two cutting planes parallel to each other, in the form of a fragment with a closed cross section, including a part of a leading edge, trailing edge, windward shell and leeward shell of the blade,
- filling the body with a filling material, and
- making its filling.