The present invention provides a permanent earth retaining wall having small diameter casings that remain in the ground to become vertical micropile soldier beams of the retaining wall, and a method for forming a retaining wall. The method includes a top-down method of constructing a retaining wall. The retaining wall may be constructed by placing a plurality of relatively small diameter micropile casings into the ground using overburden percussion drilling methods. The casings are configured to remain in the ground and form micropile soldier beams of the retaining walls. Tiebacks may be coupled to the micropiles via horizontal support wales that span multiple micropiles.