What are the advantages of a soldier pile wall?
Flexibility
Soldier Pile Walls are the go-to excavation shoring solution in densely populated urban areas such as city centers, hospital campuses, and universities. Soldier piles allow for flexibility when working around existing buildings and existing utilities. For taller walls, anchors can be installed 10′ below existing grade and can be sloped up to 45 degrees to get below existing utilities.
In the sketch below, the top row of anchors (red) were installed around existing utilities. The 2nd row of anchors (yellow) were angled more steeply and were installed below the existing utilities.
Stiffness
Solder pile walls are more stiff than soil nail walls. The anchors for the soldier piles are post tensioned for the load of the full wall height. By post tensioning the anchors as the excavation progresses, wall deflections are limited. For this reason, soldier pile walls may used when shoring near existing buildings and sensitive utilities.
While limit equilibrium analyses are most often used to design soldier pile walls, performance designs can also be done using numerical modeling software such as Plaxis to estimate the movement of the wall.
Wide Variety of Face Options
A wide variety of facings can be used on permanent soldier pile walls. Permanent walls can have a finished shotcrete face or any veneer such as brick, stone, or modular blocks. Many sites required a mix of “top-down” retaining walls such as a soldier pile wall and “bottom-up” retaining walls such as segmental block walls or cast concrete retaining walls. Since multiple veneers are possible, the all the site walls can match. We really like architectural shotcrete finishes on permanent soil nail walls such as those constructed by BoulderScape.
Ideal Soil Conditions in our Region
Soldier pile walls work well in the piedmont residual soils found in our region of Virginia, North Carolina, South Carolina, Tennessee and Georgia. Because they are constructed in 5′ lifts, the soil must have sufficient apparent cohesion to stand for 24 to 36 hours while the wood lagging is installed. With good geotechnical data and thoughtful design, unsaturated soil mechanics can be used to optimize the design.