Segmental concrete block retaining wall 1. A segmental concrete block retaining wall is a gravity or mechanically stabilized earth structure built from interlocking precast concrete units that are dry-stacked without mortar. 2. For walls above a certain height, horizontal layers of geogrid or other reinforcement are placed between courses and extend into the backfill to provide tensile resistance. 3. The modular units create a flexible system that can accommodate minor differential settlement without cracking, unlike rigid cast-in-place concrete walls. 4. The wall face is typically battered (set back) slightly with each course, and the units often include a built-in connection or lip that aids alignment and shear resistance. 5. Proper drainage behind the wall—using free-draining granular backfill and sometimes geocomposite drains—is essential to relieve hydrostatic pressure and maintain long-term stability.