Unit weight of silty sand with gravel
Unit weight of silty sand with gravel
(OP)
For till like materials (23% sub-rounded gravel, 43% sand of mainly fine grained and 33% fines) with SPT of about 50, how could one estimate the typical unit weight values.





RE: Unit weight of silty sand with gravel
RE: Unit weight of silty sand with gravel
To the OP, local experience and judgement is the best method, if you don't have a bulk sample. Then again, you can always take your nuke gauge on a field trip.
f-d
¡papá gordo ain't no madre flaca!
RE: Unit weight of silty sand with gravel
www.PeirceEngineering.com
RE: Unit weight of silty sand with gravel
RE: Unit weight of silty sand with gravel
RE: Unit weight of silty sand with gravel
RE: Unit weight of silty sand with gravel
f-d
¡papá gordo ain't no madre flaca!
RE: Unit weight of silty sand with gravel
fattdad (Geotechnical) 27 May 10 8:43
I just want to clear up the passive pressure "calculation" presented by "fixedearth."
Given Kp, the "potential" passive pressure is determined by Kp*Gamma*A*Cp (citing Brinch-Hansen), where
Kp=tan^2(45+phi/2)
Gamma=unit weight (you get to determine whether to use moist or bouyant)
A=surface area of the embedded pier
Cp= arching coefficient, typically taken as phi/10
RE: Unit weight of silty sand with gravel
Brinch Hansen, J., The Ultimate Resistance of Rigid Piles Against Transversal Forces, Geoteknish Institute Bulletin No. 12, Copenhagen, 1961.
The B-H citation provides for a value that you can use to increase the passive reaction. This value is related to the friction angle. J. M. Duncan noticed that this value is about equal to phi/10 and that's what he taught me in grad school. I don't have a copy of the orignal B-H citation so I'm going from notes.
Good luck in your search. Interlibrary loan can be your friend!
f-d
¡papá gordo ain't no madre flaca!
RE: Unit weight of silty sand with gravel
www.PeirceEngineering.com
RE: Unit weight of silty sand with gravel
f-d
¡papá gordo ain't no madre flaca!
RE: Unit weight of silty sand with gravel
When I mentioned "wall friction," I was referring to friction between the ground and the embedded portion of the soldier beam or sheet piling (which is part of the wall). I often use a "wall friction" angle of phi/2 when calculating Coulomb earth pressure coefficients. Rankine coefficients are too conservative. Some think Coulomb coefficients are unconservative. However, in designing and building a few thousand excavation support walls and sheet pile bulkheads using Coulomb earth pressure coefficients, I've never had a problem with passive resistance. I'm not saying anyone or any method is incorrect.
www.PeirceEngineering.com