Constructing a Retaining Wall on Sliding Soils

The old retaining wall (which failed) was constructed on soils that were sliding downhill!  The rock was too deep to put the new retaining wall on the bedrock, so we drilled piers down to the bedrock to stop the hill from sliding and to support the new retaining wall.

This video shows you how to prevent a retaining wall failure when there are sliding soils!


Link to Photos of this project
Joseph Kowalski, P.E.
Current State PE Registrations

Retaining Wall Failure and Rebuild 6041

Retaining Wall Failure: upper portion collapsed
When this 38-foot high retaining wall failed, Kowalski Engineering was retained to help.  Our services included determining what caused the failure, redesigning the new retaining wall, and reviewing the new wall's construction.

Many of the retaining wall blocks were reused on the project - demonstrating that these blocks are extremely durable, even after being dislodged from such a height.  You see, the large and durable block facing was not the problem.

Retaining Wall Failure: upper portion collapsed
The problems were: the type of soil used during construction, the spacing of the geogrids, and (you guessed it) water.  Remember this recipe for failure: "Just Add Water".

Good design and good construction will account for the "added water" and a retaining wall will be quite stable.  We engineered the new retaining wall and reviewed its construction.
Retaining Wall Rebuilt


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Failing Retaining Wall Pushing Building

In Cincinnati, Ohio we have our fair share of retaining wall failures: due to poor construction, poor design, or sometimes just age!  In this case, a number of factors contribute to a failing retaining wall that is literally shoving a building sideways!

Photo of failing old stone retaining wall pushing building sideways!
At this location, a natural stone retaining wall was constructed outside an apartment building.  The foundation walls of the apartment building and this stone retaining wall are supporting the land adjacent to them.

However, at some point in the past another retaining wall was added above!  This additional retaining wall was constructed just a few feet away from the apartment building.  The nearby wall is about 6 feet high, and adds a huge amount of loading to the basement/foundation wall and to the natural stone wall.

The basement wall is being held in place at the front of the building and at the middle of the building, because there are walls at a 90-degree angle to the basement wall.  Those walls are supporting the basement wall.

However, at the rear, where there are openings for the garage doors, there is little support.  The top of the garage doors has been shifted a few INCHES sideways, and the back wall of the apartment building is bulging outward.  Even the old stone wall is being pushed outward.

The owner is currently exploring options for repair!

Retaining Wall Failure - San Antonio TX

Retaining Wall Failure in San Antonio, Texas

This past Sunday (January 24, 2010) a large retaining wall failed in a San Antonio, Texas subdivision.   Initially 80 homes were evacuated when crevices up to 15 feet deep appeared after the 1000-foot long retaining wall failed.      READ MORE .....

Download attachment(s): [ Aerial View of Terrain ] [ Collapse-diagram-012610.jpg ]

Attaching Fencing to Caps--Right or Wrong?

We recently got an email asking: What is the best way to attach a vinyl fence to the top of an Allan block wall?

Our answer was: Don't, if you don't have to.....but it has been successful in the past.....(Read Full Article)