Soil at rest pressure coefficient (Ko)
Soil at rest pressure coefficient (Ko)
(OP)
This is a simple question but for some reason my mind is cloudy today.
For reasons that I will not explain here I need to know what the Ko (at rest pressure coefficient) is for a soil with an angle of internal friction of 34 degrees? I believe it is Ko=1-sin(34 degrees) but that yields a value of .4408 and at a soil weight of 120 pcf will give an equivalent fluid pressure (efp) of 53 pcf. Now the reason why my mind is so cloudy is that I have always been told to use a efp of 70 for propped walls. So my typical design value is off by a bit (note the 34 degrees was given by the geotechnical report).
For reasons that I will not explain here I need to know what the Ko (at rest pressure coefficient) is for a soil with an angle of internal friction of 34 degrees? I believe it is Ko=1-sin(34 degrees) but that yields a value of .4408 and at a soil weight of 120 pcf will give an equivalent fluid pressure (efp) of 53 pcf. Now the reason why my mind is so cloudy is that I have always been told to use a efp of 70 for propped walls. So my typical design value is off by a bit (note the 34 degrees was given by the geotechnical report).






RE: Soil at rest pressure coefficient (Ko)
One reason your efp is much lower than you may generally use is the fairly high phi angle that you are using.
To be of any additional help, would need to know how you are going to use the at-rest pressure.
Mike Lambert
RE: Soil at rest pressure coefficient (Ko)
RE: Soil at rest pressure coefficient (Ko)
RE: Soil at rest pressure coefficient (Ko)
DaveAtkins