Driving rains, excessive moisture, or extreme wind can cause topical erosion or pressurized cracks on exposed soil materials leading to slope failure. In order to alleviate the above-mentioned problems, adopting reinforcement methods is advised.
There are various methods designed for the stabilization of slopes. Most common are friction piling, benching, geo-grid retention using walls, drainage repair and shotcrete. While all serve great purposes in slope stabilization, a retention wall, in combination with geo-grid is the most commonly used method among landscape architects and landscape contractors. Any wall exceeding 4ft in height must be engineered, and requires the use of geo-grid.
Geo-grid is a synthetic material woven in bands that are arranged in a grid-like pattern with large voids between those bands, providing for stabilization of the slope in the desired location. The strength comes when the voids between the bands of geo-grid interlock with the fill material that is placed behind the geo-grid and compacted. This anchors the retaining wall to the fill material, inhibiting possible slope failure. Geo-grid will extend the life expectancy of the retaining wall and allow it to hold back greater volumes of material than if the retaining wall was built without geo-grid. Geo-grid systems provide technical basis and economic solution to severe topographic challenges, less than ultimate soil conditions, and possible land development needs.
Installing geo-grid is a straightforward process, however there is an understanding needed of the direction of strength of the geo-grid and the specified placement and length of the geo-grid with in the wall. Geo-grid is either uni-axial, providing strength in a single direction or bi-axial, providing strength in both directions. However, to achieve strong positive reinforcement, geo-grid must be installed with the strength perpendicular to the face of the wall. The grid should be kept flat and taut until desired fill material can be placed over and compacted to specified allowances.