Sloping Surcharge on Concrete Retaining Walls
Sloping Surcharge on Concrete Retaining Walls
(OP)
I am in the process of proposing on a project built on a very steep hill side. The slope of the hill is so steep, that the up hill retaining walls will encounter the condition where the 'soil wedge' behind the wall is literally hundreds of yards long. In other words the slope of the hillside (beta) is the same as the slope of the slip plane of the soil wedge behind the wall. The two planes either don't intersect, or intersect so far up hill that the soil wedge is enormous.
I am referencing the Joseph Bowles book for guidance, but would appreciate anyone's input on designing for this condition.
I see walls of similar scenario on highways that abut steep, uphill slopes so I'm assuming AASHTO addresses this situation.
The statics approach for stability would produce wall designs that are impractical. Does a correct design account for wedge to mountain friction? Is a slope
stability study with an inclinometer the first place to start? Do you soil nail or tieback the upper portions of the wall?
The hill is covered with oak brush.
I am referencing the Joseph Bowles book for guidance, but would appreciate anyone's input on designing for this condition.
I see walls of similar scenario on highways that abut steep, uphill slopes so I'm assuming AASHTO addresses this situation.
The statics approach for stability would produce wall designs that are impractical. Does a correct design account for wedge to mountain friction? Is a slope
stability study with an inclinometer the first place to start? Do you soil nail or tieback the upper portions of the wall?
The hill is covered with oak brush.






RE: Sloping Surcharge on Concrete Retaining Walls
Attached is a Navy reference that may help.
RE: Sloping Surcharge on Concrete Retaining Walls
RE: Sloping Surcharge on Concrete Retaining Walls
To give you a related example, I am now working on residence on a 20 foot high, 2:1 ascending slope. We are suggesting drilled piers and grade beam foundations. The embedment depth needed for the house is 12 ft to meet capacity and IBC setback requirement. But when I did the global static stability, I need 18 feet to be sufficiently below the failure plane. However, when I did the seismic case, I need a 22 ft embedment. So we are recommending 22 ft deep drilled pier.
In your case, the geotechnical firm will tell you what is the driving the available retaining wall options.
http://www.soilstructure.com/
RE: Sloping Surcharge on Concrete Retaining Walls
So as dcarr82775 pointed out, how do you hold back an entire mountain?
FixedEarth, thanks for the advice. I have contacted a geotech to get a sub proposal from them. My research has shown that the slope stability analysis and hardware installation seems to be key to the success of slopes this steep.