Steep slopes behind retaining walls
Steep slopes behind retaining walls
(OP)
Hi all,
If a bank (approx. 8m Ht.) of cohesive soil is excavated leaving a slope of about 60deg. (remains stable) and the owner wants to later add a retaining wall to serve as one wall of a building (garage). Should the wall be extended and the embankment re-graded to 2:1 or can the bank be assumed to be self supporting and a new wall only retain the cohesiveless backfill material?
If a bank (approx. 8m Ht.) of cohesive soil is excavated leaving a slope of about 60deg. (remains stable) and the owner wants to later add a retaining wall to serve as one wall of a building (garage). Should the wall be extended and the embankment re-graded to 2:1 or can the bank be assumed to be self supporting and a new wall only retain the cohesiveless backfill material?





RE: Steep slopes behind retaining walls
f-d
¡papá gordo ain’t no madre flaca!
RE: Steep slopes behind retaining walls
RE: Steep slopes behind retaining walls
RE: Steep slopes behind retaining walls
good luck
RE: Steep slopes behind retaining walls
I have worked on steep slopes under conditions where you cannot flatten them because of terrain or property ownership (or lack thereof).
These generally have to maintained to prevent erosion, but it is an ongoing thing that cannot be neglected. We generally have found it is not practical for high slopes to consider a full height retaining wall. A few have worked OK with a gravity retaining wall only at the base mainly to keep that area from dribbling earth into a work area below. Erosion above is what has to be controlled. Keeping runoff from above seems to be the main need to limit this erosion and local slips.
6
I also have seen several 60 degree slopes "paved" with heavy stone, treated with drainage filtration behind them. One near here where I did the design 27 years ago, is still holding fine, but neeeds a little maintenance now and then. Height of the stone "paving" was about 10 to 20 feet Land above that is a 39 degree slope wooded for a long ways. In that case the owner US Govt. agency knows of the risk and what is involved for maintenance. The treatment is mainly for limiting erosion, not for holding back anything. Soil type is silty clay, weathered loess. If it comes down there is only a parking lot below.
RE: Steep slopes behind retaining walls
The situation is more or less as oldestguy says. My problem would be that i don't think this approch can be justified via calculation (slope angle is much more the the soils angle of internal friction.
RE: Steep slopes behind retaining walls
Cohesion from simple unconfined compression tests was quite good. Critical height on that basis was pretty hig also, but there was no way the funds would pay for a better job.
We didn't go so far as to figure losing this cohesion with time, but this got the job going for now. It seems to be rather "permanent" in spite of possible failure some time later.
I suppose we could have told the owner "no way" and walked off.
RE: Steep slopes behind retaining walls
Thread 255-186861 has a reference to a US Govt. publication for Rockery Walls, generally under the class of gravity walls. However, some of the reference work is analysis of these walls with sloping front face. Sort of applies here I think.
Interesting to see the ratio of base width of the rocks to height can be much more than the rule of thumb (3)for sloped back face of wall situations.
RE: Steep slopes behind retaining walls
RE: Steep slopes behind retaining walls