Active and Passive Pressures for Bedrock
Active and Passive Pressures for Bedrock
(OP)
We are working on foundation design recommendations for spread footings that will bear directly on bedrock. Sliding is a concern of the structural engineer and would like recommendations on active and passive pressures if a shear key is installed.
I have lots of references which deal with soil, but none that deal with rock for this problem. Any suggestions on where to look?
I have lots of references which deal with soil, but none that deal with rock for this problem. Any suggestions on where to look?





RE: Active and Passive Pressures for Bedrock
RE: Active and Passive Pressures for Bedrock
RE: Active and Passive Pressures for Bedrock
RE: Active and Passive Pressures for Bedrock
Going from memory, the rock I'm dealing with is moderately fractured with steeply dipping fracture planes. I could do tests on individual pieces of rock, but I don't believe that gives me an accurate value for the entire rock mass.
Any more ideas?
RE: Active and Passive Pressures for Bedrock
If it's still an issue, try to find "Rock Slope Engineering" by Evert Hoek and John W. Bray, Institution of Mining and Metallurgy, 3rd edition, 1981, pp. 107 - 110. There is an empirical relationship for rock-mass strength based on jointing, weathering, rock type, confining stress, etc. It's in the form of equations and a big table for the parameters, so I won't try to reproduce it here.
You are correct that testing individual pieces of the rock won't tell you a whole lot about the strength of the rock mass on a gross scale.