US Patent 6877290 Building block

A plurality of building blocks (1) form a retaining wall (300), which may be curved, with respective side edges (6, 7) providing pivot points and a stepped base (5) of an upper block (1) being positionable on the upper surface (4) of a lower block (1). The gaps between the blocks 1, and their permeability, being made from permeable concrete, can avoid hydrostatic build up behind the wall (300). The permeability of the concrete used for the blocks (1) is in the range of 10−2 m/s to 10−4 m/s and may be in the region of 6.00×10−3 m/s.