Soil Nail Design

[dpa]

I am looking for information to help determine the quantity, spacing and depth of soil nails. The site is a steep slope about 45 to 55 degrees and about 150 feet high. Soil is fine sand with just enough silt to form solid but easily broken lumps when dug with a shovel. Lab tests will be performed later this week.

There is a timber bulkhead on top which varies in height from 10 to 18 feet along a length of 250 feet. The base of the wall is undercut by mountain beaver tunnels.

I know how to figure out the active area behind a typical retaining wall or bulkhead but am a bit fuzzy about the combined geometry of the two active areas (bulkhead plus unrestrained slope).

Thanks,
DPA

 

[RCEJD]

FHWA, Caltrans and University of California Davis all have publications and programs that you can use.

 

[dpa]

Hi RCEJD,

Thanks I'll check them out.

DPA

 

[PEinc]

You have a very large and steep hill. I hope the project geotec has run a slope stability analysis. Were a good subsurface investigation and lab testing performed? Any slope stability analysis or soil nail design is only as good as the accuracy of the subsurface profile and soil or rock design properties.

 

[dpa]

Not yet. Just in the proposal stage

DPA

 

[RCEJD]

http://www.fhwa.dot.gov/bridge/geopub.htm#reinforcedsoilstructures