ABCDEFGHIJKLMNOPQRSTUVWXYZ ACTIVE SOIL The soil behind the wall that will theoretically move. AT-REST SOIL The soil behind the wall that will theoretically not move. BACKFILL The soil used to fill the excavated area behind the wall. BASE COURSE A full course of blocks which are buried so that the top is level with grade. See product-specific installation instructions for any exceptions. BATTER The facing angle created by segmental retaining wall (SRW) unit setback, measured from a vertical line drawn from the toe of the wall, expressed in degrees. BENCH CUT A horizontal cut across a slope. Commonly used when building steps into an existing slope. COLUMN A vertical pillar, generally used as a support for a wall or other structure. COMPACTION Compressing or densifying the soil material used for base and backfill. CONNECTION STRENGTH TESTING Testing establishing the relationship between a specific SRW unit and a specific type of geosynthetic reinforcement. COURSE A horizontal layer of blocks used to build a wall. CREST SLOPE Angle of the soil above the wall usually expressed as a ratio such as 3:1 (3 feet horizontal to 1 foot vertical). DRAINAGE AGGREGATE Drainage fill placed within and immediately behind the SRW units, and in other areas, for drainage. FINES The smaller particles of aggregate. FOUNDATION SOIL The soil that supports the leveling pad and the reinforced soil zone of a soil-reinforced SRW system. FREE STANDING WALL (FSW) A vertical wall which does not retain soil. Also called a double-sided wall. GEOGRID A synthetic material formed into a grid-like structure for use in soil reinforcement. Usually composed of polypropylene, polyester or polyethylene. GEOSYNTHETIC A generic term used to describe synthetic or plastic materials used in soil, such as fabrics, geogrids, drainage composites or erosion-control mats. GEOSYNTHETIC-REINFORCED RETAINING WALL A geosynthetic-reinforced wall needs to be designed by a qualified engineer. With a reinforced retaining wall there are (theoretically) no height limitations, and they are used in larger applications. They require more work area behind the structure. The block of soil is stabilized by introducing reinforcement layers into the soil mass behind the facing units. The larger the stabilized soil mass, the more soil can be retained or held back. The geosynthetic reinforcement in the soil extends past the theoretical failure plane and serves to create a large, rectangular mass of block and soil, restraining the retained soil. GEOTEXTILE A textile-like material used in soil drainage and reinforcement applications. Usually composed of polypropylene or polyester, it can be woven or non-woven. GLOBAL STABILITY Resistance to overall mass movement of the SRW system in a circular or sliding mode. May be a problem with tiered walls, walls with weak foundation soils, and walls with a slope at the top or bottom. GRADE Ground level. GRAVITY WALL A retaining wall that does not use soil reinforcement. A gravity wall relies on the weight and setback of the block to resist the soil forces that are being exerted on the wall. LEVELING PAD AGGREGATE A compactible, free-draining granular soil to facilitate compaction and drainage. LEVELING PAD OR BASE The level surface (gravel or concrete) used to distribute the weight of the dry-stacked column of SRW units over a wider foundation area and to provide a working surface during construction. LOAD OR SURCHARGE, DEAD A permanent surcharge on a wall that can provide lateral pressure against the wall as well as vertical force downward on the wall mass. LOAD OR SURCHARGE, LIVE A transient surcharge that can vary during the life of the structure. A live load is assumed to provide lateral pressure but not vertical pressure. OVERTURNING An external stability failure mechanism of an SRW whereby lateral external forces cause the entire reinforced soil mass to rotate about the base. PERMEABLE SOIL A soil that allows water to move through it at an appreciable rate. PILASTER An upright architectural member that projects from the wall. PILLAR A firm upright support for a superstructure. PROCTOR (DENSITY) A method for determining the moisture-density relationship in soils subjected to compaction. REINFORCED SOIL ZONE The area of a soil-reinforced SRW which contains the soil reinforcement. RETAINED SOIL ZONE The area of a soil-reinforced SRW which is immediately behind the reinforced zone. RUNNING BOND A staggered vertical alignment used to create a consistent pattern. It may be necessary to use split or partial units to maintain a running bond. SEGMENTAL RETAINING WALL (SRW) A wall system built with modular blocks to retain soil. SLIDING An external and internal stability failure mechanism of an SRW whereby lateral external forces cause the entire soil mass to slide forward along its base or internally along a particular layer of soil reinforcement. STEPPING UP THE WALL BASE Method used to maintain a level wall on a slope. SURCHARGE External load, usually applied at the top of a SRW. A roadway or building foundation can be a surcharge. SWALE A small ditch or depression formed on top and behind the SRW system to collect water and carry it away. TERRACED WALLS Two or more walls set above or below each other. THEORETICAL INTERNAL FAILURE PLANE The line that separates active soils from the at-rest soils. TOE SLOPE Angle of the soil in front of the wall usually expressed as a ratio such as 3:1 (3 feet horizontal to 1 foot vertical). More questions? You can contact us at Anchor Wall Systems, 5959 Baker Road, Suite 390, Minnetonka, MN 55345 or 1-877-295-5415.