Monday, February 20, 2017

Retaining Walls

Retaining walls may be used to support steep slopes when the earth materials lack adequate strength, or when there is not enough space for a slope. In order for a retaining wall to be stable, its design must include all of the loads that it will support. Converse’s engineers have provided geotechnical recommendations and parameters for the design of numerous types of retaining walls.

Cantilever retaining walls are usually constructed of concrete and include a large footing at the base of the wall. The space behind the wall is backfilled with compacted fill soil. Important considerations are the pressure exerted by the retained soil, the weight of the backfill, drainage behind the wall and compaction of the backfill.

Mechanically stabilized earth walls typically consist of interlocking masonry blocks with layers of synthetic geo-grid extending behind the wall into compacted fill. Drainage is not generally an issue, but the geo-grid material and spacing must be designed based on the correct loads and soil characteristics.

Soil nail and rock bolt walls use steel rods to stabilize a soil or rock slope. Depending on the geologic conditions and wall design, the rods may be held in place by friction, epoxy, or mechanical anchors. The exposed end of the soil nails or rock bolts may be treated cosmetically or a structural concrete facing may be required to retain the earth material at the slope face. The success of this type of wall depends on accurate characterization of the materials in the existing slope and appropriate geotechnical recommendations for the size, strength, spacing and placement of the soil nails or rock bolts.