This is a practice common in harbour and port areas, but also in other areas. It is generally known as ground raising. In harbour areas it is commonly performed by dredging and pumping the sand and gravel onto land to raise the ground level (for example for raising the level of a building site for plood protection). As this specifies 'Trocken' I would use the term suggested above, where (ground) is optional (although I would probably use it). Take a look at the file below, for example.