What is a Segmental Retaining Wall System? A Segmental Retaining Wall system comprises of a set of interlocking stackable block units, which combine to form your wall. A similar principle to that of Lego blocks. By JT's|2018-11-10T22:04:32+00:00November 10th, 2018|Retainig Wall| Share This Story, Choose Your Platform! FacebookTwitterLinkedInWhatsappPinterestEmail