The part of Antarctica where Halley VI is located at, Brunt Ice Shelf, experiences annual snow accumulation of anywhere between 1 and 2 meters. To counteract that, all buildings and structures around Halley, as well as the main modules, have to be raised each year. Failing to do so would condemn them to be buried and in just a few years time they would get completely covered.
Depending on the structure, the techniques employed to do the raise vary, but generally the simplest methods are preferred. To raise a Caboose (which is effectively a container on stilts), a set of four hydraulic, manually operated jacks are used - one per leg. These are placed on "shoes" (a steel element protruding off a leg, which can be moved up and down and locked in position with a pin). Then, Steel Erectors operate all four jacks simultaneously and the building is raised about 10cm at the time. After that, the caboose is locked in place (again using the steel pins), the jack removed and compressed, the shoe moved one hole up, and the process starts again, until the caboose is raised a least 1-2 meters above its previous level.