Blog Archives

8.5.1 Types of MSE Walls

Mechanically stabilized earth (MSE) walls are made up of several elements—specifically, the reinforcement of a soil mass through the use of steel strips, steel or polymeric grids, or geotextile sheets, capable of withstanding tensile forces, and a facing material. Figure 8.25 depicts different types of geosynthetic reinforced walls. The walls depicted range from a sloping geotextile wrapped face, usually used for the more temporary

Vertical cast-in-place Vertical masonry facing

concrete/masonry facing

FIGURE 8.25 Facings for geotextile-reinforced walls.

conditions, to stabilized soil masses faced with more long-term cast-in-place concrete or masonry block facings.

The advantages of MSE walls over the more conventional reinforced concrete walls include

1...

A typical cantilever retaining wall is illustrated by the insert sketch in Fig. 8.21. This rigid-type wall can be constructed with or without a base shear key (see Fig. 8.20) depending on an analysis for resistance to sliding, as discussed later.

The specifications of the owner will govern the selection and use of backfill materials behind retaining walls. In most cases, clean backfill materials having an internal friction angle of at least 34° are assumed in the design of retaining walls, subject to the fol­lowing considerations:

1. With a proper drainage system and with backfilling controlled so that no compaction-induced lateral loads are applied to the wall, the above-noted or better material may be used in construction. A minimum lateral earth pressure of 30 (lb/ft[10] [11])/ft (4...

Where retaining walls are underlain by weak soils, the overall stability of the soil mass containing the retaining wall should be checked with respect to the most critical surface of sliding. A minimum safety factor of 2.0 is desirable but may not always be achievable. A technique known as slip circle analysis can be used to check for global stability. Refer to standard texts on soils engineering.