Abstract: A support having a corrugated wall and a generally conical shape is insertable into a foundation material such as sand or dirt. During insertion, the lower end flares outwardly until the corrugations are fully expanded, whereupon the tensile strength of the wall forming the tubular body resists further expansion. The greatly increased surface area presented transverse to the direction of insertion, causes a large increase in resistance. The member with its base expanded can then be filled with concrete or other filler material and used as a stable foundation support.