good way to design a shear key -cantilever retaing wall - sliding

[gaurav441982]

Hi ,

I am designing a retaining wall 9.5 ft high holding 9 ft of soil and with 2 ft of soil on front side ( passive side)with frost protection for 2 ft, thus I need a shear key to check sliding .

What are the options in the industry to do a good shear key design ?


Thank you


- GP

 

[kslee1000]

What is the type of soil below the base mat? What is the friction angle, and/or cohesion value? How far is the water table below the base mat? What type of backfill material you intend to use, and its properties? Give us some more information would help to provide better responses.

 

[msquared48]

If you dig down about a foot to 18" below the wall footing at the wall (the width of the wall), that should be in the ballpark when you run the numbers.

Mike McCann
MMC Engineering

 

[JedClampett]

A lot of Geotechnical Engineers reduce the friction value on a retaining structure when you use passive pressure. So the shear key is not a "free" increase in sliding resistance. It may be easier to increase your heel length to get more weight on the wall.
I've noticed that State DOT standard retaining wall details (TX, for example) only use very short keys (like 9") which tells me that they're not depending on them very much.

 

[kslee1000]

Agree with Jed, while shear key helps, it has undesirable side effects. Adding weight (thicken, or enlarge, the baseis) is better approach.