Foundations on Silt
Foundations on Silt
(OP)
Does anybody have experience of foundations on silt / siltstone. Or know any decent guidance.
We have a small domestic job where we will be building on silt / siltstone. We have a lot of trees on site and im wondering if silts are subject to heave and shrinkage due to trees in the same way clays are?
We will be using a raft but im interested to know if the ground is going to move.
Thanks
Countervail
We have a small domestic job where we will be building on silt / siltstone. We have a lot of trees on site and im wondering if silts are subject to heave and shrinkage due to trees in the same way clays are?
We will be using a raft but im interested to know if the ground is going to move.
Thanks
Countervail






RE: Foundations on Silt
Based on code BS 8004:1986, silt soil has a NIL bearing capacity and yes, it triggers 'heave' warning!
RE: Foundations on Silt
You need to get a geotechnical engineer with local experience involved with the project.
Mike Lambert
RE: Foundations on Silt
RE: Foundations on Silt
RE: Foundations on Silt
If you also have a water source and cold winters, it could be an issue.
RE: Foundations on Silt
Most appreciated, by domestic job I mean a house extension where I can't persuade the home owner to get an geotechnical investigation done!
In this case I did some in house testing and decided it's silt with a little clay (probably low plasticity) and treated it as a high plasticity soil with an allowable bearing pressure of 50kN/m^2 (i.e close to soup, which it isnt) and went for a raft on 1m of compacted gravel.
I have a real problem with small jobs persuading clients to pay for a site investigation as they always ask "will it save me money" and when we say it might they won't pay "I'm not paying that if all its not gonna save me money and it's gonna take me weeks to get". I need to work on my people skills.
RE: Foundations on Silt