Particle size, cobbles, gravels for Liquefaction

[pgyr]

A silty/clayey gravel stratum, SPT sampling, 25-35 ft depth with water table at 18 feet. Loose to medium dense. SPT samples yield fragments of larger gravels which, coupled with experience in the area, indicates to us that there is a significant percentage of cobbles to gravels. Liquefaction determination per Idriss and Boulanger 2008 indicates liquefaction for the MCE per ASCE 7-16.
In our practice here in Jackson Wyoming, we commonly run into cohesionless cobble/gravel/sand alluvium below the water table-in almost all case density /shear wave velocity is too high for liquifaction-never had to deal with this issue before.
Kramer 1996 has a general statement that poorly graded angular gravels and cobbles are less susceptible to liquefaction. The paper below regarding ejected material which would seem to indicated D50 over a certain size is not liquefiable.

http://www.iitk.ac.in/nicee/wcee/article/13_1190.pdf

Is there a definitive reference or references regarding particle size vis a vi liquifaction?

 

[Lomarandil]

NYDOT references Tsuchida (1970) on page 25:

https://www.dot.ny.gov/divisions/en...ices/technical-services-repository/GDP-9b.pdf

----
just call me Lo.

 

[GeoEnvGuy]

All deposits which can generate excess pore pressures are liquefiable. In California dense sands are liquefiable but the result is they dilate and fail to the critical state line.

In your case of lower permeability material above a loose deposit of higher permeability there is the added uncertainty of a water film forming at the interface which will have no shear strength.

You can review the liquefaction state of the art paper 2016 and usbr 2015 design standard 13 seismic for the most recent on gravely soils liquefaction.

 

[pgyr]

GeoEnvGuy, Thanks.

 

[pgyr]

GeoEnvyGuy, Title of the state of the art paper 2016?

 

[GeoEnvGuy]

State of the Art and Practice in the Assessment of Earthquake-Induced Soil Liquefaction and Its Consequences

 

[Okiryu]

Attached are some research papers about liquefaction susceptibility for gravels.

 

[Okiryu]

Another one. I was looking at the reference recommended by GeoEnvGuy and it is good. The last year NAS have a free webinar about that publication...

 

[GeoEnvGuy]

If you cannot characterize the cobbles and gravels with a CPT or SPT's you can consider the instrumented Becker penetration test to provide a characterization of gravelly soils.

Resource for the Instrumented Becker Penetration Test
Instrumented Becker Penetration Test 2: iBPT-SPT Correlation for Characterization and Liquefaction Assessment of Gravelly Soils

Also there is a state of the art paper in 2016 from the USBR on Graves themselves
Liquefaction Triggering Assessment of Gravelly Soils: State-of-the-Art Review

 

[pgyr]

GeoEnvyGuy,
Thanks.