Earth Support · Cambridge
Property-Line Soldier Pile Walls, 194–196 Lakeview Ave
A new building at 194–196 Lakeview Ave is dug out to its property lines on four sides. Every wall has a neighbor behind it, the design carries a 250 psf surcharge, and groundwater sits 6–10 ft down in silt and sand.
The problem
A new building at 194–196 Lakeview Ave is dug out to its property lines on four sides. Every wall has a neighbor behind it, the design carries a 250 psf surcharge, and groundwater sits 6–10 ft down in silt and sand.
The engineered approach
Twenty-four HP12x53 soldier piles go into 18 in drilled holes backfilled with flowable fill, about 7 ft exposed over 12 ft of embedment, at 8 to 10 ft spacing along roughly 194 lf of wall. Timber lagging follows the excavation down. The walls are cantilevered to the project's PE-stamped support-of-excavation design, and the rest of the dig is sloped back.
Where it stands
- Underway now: four property-line walls, 24 soldier piles
- Built to the project's PE-stamped SOE design
- Cantilevered walls, with no tiebacks or bracing in the dig
How we're building it
A schematic section of the earth support system for this Cambridge job. Scroll to build it in construction order, or select a callout to read the detail.
Callouts
Select a numbered part below to read what it is and what it does.
- Each of the four walls sits on a property line with a neighbor behind it. The walls are cantilevered, so nothing is anchored under the neighbor's lot and nothing braces across the dig.
- The PE-stamped support-of-excavation design (by others) carries a 250 psf surcharge on the neighbor's side, where surface grade varies. ESC installs the piles and lagging to that design.
- Each pile is set in an 18 in drilled hole and backfilled with flowable fill. The fill locks the pile into the silt and sand, and the excavation simply takes it away in front of the flange when the dig comes down.
- Twenty-four HP12x53 piles at 8 ft and 10 ft spacing make about 194 lf of wall. Each stands about 7 ft above the bottom of the excavation over 12 ft of embedment, about 19 ft in all, and the embedded length is what holds the cantilever.
- As the excavation comes down, ESC sets 3 in timber lagging between the pile flanges, so the soil between piles is only ever open one lift at a time.
- Groundwater is 6–10 ft down, so it can stand above the 7 ft cut and the whole embedded length is below it. Dewatering by others keeps the water at least 2 ft below the bottom of the excavation while the walls are open.
- Borings (July 2025) found granular fill with some organics 1–6 ft thick, over stiff silt with fine sand lenses and traces of clay, over medium dense to dense stratified sand with some silt and gravel. Bedrock was not encountered.
Ready to scope your foundation?
Tell us about the project and we'll put together a detailed quote within 3 days. We generally work with general contractors.
Or email plans to bids@earthsupportcorp.com