Device for anchoring in multilayer soil

A device for anchoring in multilayer soil having a hollow rod which includes a first end which can receive a fastening means and a free opposite end intended to drill into the ground, in which a positioning plate is mounted on the hollow rod and is intended to bear on the surface of the soil, the rod successively including, from the positioning plate towards the free end, at least one helical force disc then a helical drilling disc, wherein the rod extends beyond the helical drilling disc opposite the positioning plate, and wherein a bit is arranged on the free end of said rod, such that a first part of the rod, suitable for being screwed into at least one first soil layer, extends from the positioning plate to the helical drilling disc, and such that a second part of the rod, suitable for anchoring in a second soil layer, extends from the drilling disc to the bit;

• wherein the hollow rod has between the at least one helical force disc and the helical drilling disc at least one helical intermediate disc having an external diameter wherein the external diameter of the at least one helical intermediate disc is between an external diameter of the at least one helical force disc and an external diameter of the helical drilling disc;
• wherein the multilayer soil includes at least one first soil layer having a thickness of loose material, the first layer resting on a second layer which includes one or more monolithic or consolidated materials;
• and wherein the bit is a self-drilling bit having rigidity for drilling into the second soil layer;
• wherein the at least one helical intermediate disc is formed by a continuous conical spiral, connecting the at least one helical force disc and helical drilling disc, respectively;
• wherein a cylindrical casing is formed around the first part of the rod, between the positioning plate and the helical drilling disc;
• and
• wherein the hollow rod is threaded over at least the second part extending between the helical drilling disc and the bit, and the hollow rod is smooth in the first part surrounded by the cylindrical casing.