Wall Friction Angle (delta) for passive pressure calculation for soldier pile walls
Wall Friction Angle (delta) for passive pressure calculation for soldier pile walls
(OP)
In using Caquot and Kerisel method to estimate passive earth pressure coefficient Kp (AASHTO Fig 3.11.5.4-2), for the special case of soldier pile and lagging wall (drilled shaft / H-pile), is it more prudent to ignore wall friction?
I would like the opinions of the more experience engineers here.
Per FHWA-NHI-10-016 Drilled Shafts manual (page 12-50):
"For passive earth pressure, large values of wall friction with a wedge-type
solution derived from Coulomb theory can be unconservative and therefore it is recommended that wall friction be taken as zero."
Per NAVFAC DM7-02 (page 7.2-112):
"For granular soils, determine K+p, without wall friction".
Per civil tech shoring suite manual:
"The wall friction in the passive zone is insignificant should be ignored because the area within the soldier pile is too small"
In your experience in designing soldier pile walls what value of delta do you typically use? What range of Kp values have you use before? Does Kp values >20 sound unreasonable?
Thanks
I would like the opinions of the more experience engineers here.
Per FHWA-NHI-10-016 Drilled Shafts manual (page 12-50):
"For passive earth pressure, large values of wall friction with a wedge-type
solution derived from Coulomb theory can be unconservative and therefore it is recommended that wall friction be taken as zero."
Per NAVFAC DM7-02 (page 7.2-112):
"For granular soils, determine K+p, without wall friction".
Per civil tech shoring suite manual:
"The wall friction in the passive zone is insignificant should be ignored because the area within the soldier pile is too small"
In your experience in designing soldier pile walls what value of delta do you typically use? What range of Kp values have you use before? Does Kp values >20 sound unreasonable?
Thanks





RE: Wall Friction Angle (delta) for passive pressure calculation for soldier pile walls
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RE: Wall Friction Angle (delta) for passive pressure calculation for soldier pile walls
In this instance, I'm approximating Cp as phi/10. You can do a chart lookup if you want to.
So for a soil acting on a 12-in pile that has at least 3-fold pile-to-pile spacing and penetrating soil with a friction angle of 30 degrees, I'd get a Kp value of 9.
f-d
¡papá gordo ain’t no madre flaca!
RE: Wall Friction Angle (delta) for passive pressure calculation for soldier pile walls
Have you ever use the AASHTO fig 3.11.5.4-2.
For the special case of vertical wall with sloping backfill, what value of beta should one use.
For example:
phi=34, beta=+32, horizontal bottom of excavation,
I am under the impression that even with a sloping backfill, AASHTO fig 3.11.5.4-1 (assuming beta=0) should be used in the case of horizontal bottom of excavation, is that right?
Thanks
RE: Wall Friction Angle (delta) for passive pressure calculation for soldier pile walls
For a soldier beam with level soil in front of the beam embedment, beta is 0 degrees. Sometimes, the ground surface slopes down (negative beta) and the Kp will be reduced.
If the ground is level in front of the soldier beam wall, beta/phi = 0.
I may be wrong, but you seem to be a little bit confused about the graphic for 3.11.5.4-2 which shows a vertical wall being pushed back into the soil. For a soldier beam, the passive soil is in front of the beam and is not normally referred to as backfill.
www.PeirceEngineering.com
RE: Wall Friction Angle (delta) for passive pressure calculation for soldier pile walls
And yes, the aashto fig 3.11.5.4-2 was a bit confusing.
you said "PADOT requires use of Rankine earth pressure coefficients". Is this in DM4 or in specification? Or is it just your experience dealing with their design review unit?
Thanks
RE: Wall Friction Angle (delta) for passive pressure calculation for soldier pile walls
http://www.soilstructure.com/
RE: Wall Friction Angle (delta) for passive pressure calculation for soldier pile walls
www.PeirceEngineering.com