Shotcrete Faced Reinforced Soil Slope

[DScintille]

We are in the process of designing a reinforced soil slope (RSS) for a client/owner. The slope is part of a containment dike for a tank. The slope has to have a facing that will not promote vegetation growth. We're contemplating either a shotcrete or geomembrane facing.

Does anyone have any experience with shotcrete faced RSS? We are also looking to find order-of-magnitude numbers for costs per square foot for a welded wire shotcrete face on a 1H:1V slope in the Midwest.

Any recommendations would be greatly appreciated.

 

[jdonville]

DM,

You could contact a soil nail wall installer - these are typically constructed with shotcrete facing at near-vertical slopes.

Jeff

 

[DScintille]

Agreed. We have designed many soil nail shotcrete walls (primarily in the northwest), but I have never done one on an RSS. We are looking at installing deadmen anchors to tie the facing to the slope.

Does anyone have contact information for a reputable shotcrete contractor that does at least soil nail type shotcrete work?

-D

 

[cvg]

soil nails and shotcrete are likely to be done by separate specialty subcontractors. Shotcrete contractors are quite prevalent, at least around here - but most of them would not do the soil nailing. I would recommend calling your local / state DOT and ask for a few references. They may also be willing to share some cost info for the work.

 

[DScintille]

I don't think we will be considering soil nails in the fill (Reinforced Soil Slope), but we are considering using deadmen embedded within the reinforced soil. We are primarily focused on getting shotcrete prices for budgetary purposes right now.

I'll call the DOT as you suggested.

Thanks for the help.

-D

 

[civilperson]

Compare with slope paving at bridge abutments. Higher quality at a lower installed cost!

 

[cvg]

depending on size of job, complexity etc. I use something like $30 - $50 per square yard for 3,000 psi shotcrete. Typically 4" thick minimum with welded wire mesh reinforcement. This also includes fine grading, subgrade prep and compaction etc. Doesn't include any slope reinforcing such as nails or geogrid.

 

[MSEMan]

If the containment dike is for anything flamable forget about geomembranes (and geosynthetic reinforcement as well.)

One very inexpensive way to inhibit plant growth is to use open graded stone (#3 or #4) in first 2-3' of the face behind a wire facing. Separate this from the main backfill with a woven geotextile such as Mirafi HP370. Whle the standard wire basket is W4 @ 4" Both Tensar out of Atlanta and EarthTec out of Leesburg, VA offer systems that have facing baskets with 2" vertical wire spacings that will hold a 3" stone without any spill.

You may also want to consider back to back vertical precast faced MSE walls for the dike. You'll get the design and MSE materials for about 12-$14 / s.f. from either TRICON, RECO or EARTHTEC in the MidWest. All use steel reinforcement which will help if there's a fire. One benefit of this arrangement is that it will minimize the amount of imported fill, you may find that its the most economical solution.

Hope this helps.

 

[JML4TCM]

Typical installed cost of a 1H:1V Geosynthetic reinforced wire basket slope is about $8 to $12 per square foot of face. Not sure how much the shortcrete would add to the cost.

 

[gsl2007]

We are working on a project in the Caribbean where we have expansive clays and a tropical climate. Is this application a possibility for these types of soils. Slopes range from 2H:1V to 4H:1V and are 10-20m in height.

Has anyone used any contractors for similar work in this region or aware of any contractor(s) who may be willing to discuss this option.

Retaining walls are not the preferred option due to cost.

 

[TLB171]

CAN-USA
201-996-9287

Specialty access, steep slopes

http://www.can.ltd.uk/index.htm

 

[Riggly]

gsl2007 there are a lot of development in slope stability. I would not reccommend using just shotcrete to stabilize slopes of that height. Have you performed a slope stability analysis? Stotcrete is normally used as a 'cover'- expansion of the soil will crack the shotcrete easily. To make it work, it will have to be reinforced, and thickened, and you will eventually have a retaining wall. If you need the shotcrete to control surface infiltration- that could work.

Can you say more about your project?

MGyver- I recently worked with shotcrete in a pond, but it is on the east coast. we used fiber reinforcement in the shotcrete to control shrinkage cracking. You might want to do that in addition to your reinforcement for this containent, if u are not using a liner. We actually had a liner under the shotcrete, and I strongly recommend it, because the shotcrete is going to crack.