PURPOSE: To provide a reinforcing material adaptable to different soil sorts by installing band-shaped drain material at a certain spacing on a sheet member consisting of a lattice-form meshing, and laying it in a banking at certain thickness intervals with a mild gradient is provided.

CONSTITUTION: To at least one surface of a grid 13 as a sheet member consisting of a lattice-form meshing of plastic, band-shaped drain material 14 is adhered parallel at a certain spacing by heat fusion welding, pressure attachment, adhesives, etc., so that a reinforcement 10 is formed. This drain material 14 includes a core consisting of a plastic thin plate having surface unevenness to serve as a watercourse for draining, and to the surface of the core, a non-woven cloth of plastic is affixed as a filter material. The reinforcement 10 is laid in a banking 11 as covering a specified thickness of banking layer while a mild gradient is provided inclining downward from the center to the slope face. The grid 13 strengthens the shear strength while the drain material 14 improves water exhaust. Thereby a banking reinforcement is achieved which is applicable both to a sandy and clayey soil.