Photo Album: Castaic, Ca Helical Anchor for Lateral Suppot Retaining Wall Demolition Demo of retaining wall Excavator at work Tiebacks Excavator at work Tiebacks Helicals New construction helicals in grade beam trench Tiebacks Installing pre-construction tiebacks to provide lateral support for a new retaining wall. Pre-Construction applications are a "preventative" solution in which they are installed prior to the concrete being poured, to ensure settlement can not occur.