Patent ID: 7025539

Claim:
A structural panel fabricated of synthetic resin material for driving into soils and forming walls, piers, and dikes, comprising: said structural panel being elongated and of constant size and shape along its length and shaped for being continuously manufactured in one piece; said structural panel including in cross section: a central wall section including an inner surface, an outer surface, and opposed side wall sections co-planar with said central wall section and forming with said central wall section a substantially flat outer surface of the structural panel; a male locking element disposed on and extending laterally from one of said side wall sections, a female locking element disposed on and extending laterally from the other of said side wall sections, said female locking element being configured to slidably receive and retain said male locking element of a duplicate structural panel, said male and female locking elements configured not to protrude beyond the substantially flat outer surface of the structural panel; and first and second strengthening flanges integrally formed on said inner surface, said first and second strengthening flanges being both substantially perpendicular to said central wall section and to said side sections and substantially parallel to each other, said first and second strengthening flanges extending along said length of said structural panel and with said central wall section forming a U-shape with the opening of the U-shape facing away from said central wall section such that access is available between the strengthening flanges along the length of the structural panel.