A hole (6) is provided in soil or a structure, and an injection bar (1) having a fillable expansion element (2) in connection therewith is arranged into the hole. A substance which expands as a consequence of a chemical reaction is injected into the expansion element (2). The expansion element (2) filled with the reacted substance condenses, fills or replaces surrounding soil or lifts as well as stabilizes ground-based structures. A force pressing the expansion element (2) against the soil is generated by the chemical reaction which expands the substance injected into the expansion element (2).