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 Subject : Liquefaction Settlement & Clay Crust.. 07/31/2020 12:53:32 PM 
Kelly Cabal
Posts: 26
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Does anyone know of a reference that quantifies the prediction of settlement at the ground surface when the liquefaction conditions are underlaying a thick, non-liquefiable clay crust? The reference would need to be DSA/CGS review worthy. Example condition: 35 feet of crust over interbeded sands with 2.5 to 3.5 inches of potential settlement from 35 to 45 feet; SPT evaluation.

Submitted by a CalGeo member.
 Subject : Re:Liquefaction Settlement & Clay Crust.. 07/31/2020 01:13:50 PM 
Robb Eric S. Moss
Posts: 1
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Key references when dealing with an overlying non-liquefiable crust are:

Ishihara, K. (1985) “Stability of Natural Deposits During Earthquakes.” Proc. 11th Int. conf. on Soil Mechanics and Foundation Engineering, Vol.1.

Youd, T. L., and Garris, C. T. (1995). “Liquefaction-induced ground- surface disruption.” J. Geotech. Eng., 10.1061/(ASCE)0733-9410 (1995)121:11(805), 805–809.

Robb Moss
 Subject : Re:Liquefaction Settlement & Clay Crust.. 07/31/2020 01:14:37 PM 
Robert Pyke
Posts: 3
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See:

Crawford, C., Tootle, J., Pyke, R. and Reimer, M., “Comparison of simplified and more refined analyses of seismic settlements”, Proc. 7th International Conference on Earthquake Geotechnical Engineering, Rome, June 2019

Pyke, R., “Improved analyses of earthquake-induced liquefaction and settlement”, Proc 7th International Conference on Earthquake Geotechnical Engineering, Rome, June 2019 (a)
 Subject : Re:Liquefaction Settlement & Clay Crust.. 08/03/2020 01:12:16 PM 
Jennifer Thornburg
Posts: 1
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In addition to these, I would recommend Ishihara (1995). But I caution that these papers are discussing the hazard of surface manifestations of liquefaction – such as sand boils, ground fissuring, loss of bearing capacity. These guidelines are NOT actually applicable to the seismic settlement question.

I am also aware that the paper by Cetin, Bilge, Wu, Kammerer & Seed (2009) includes a depth-weighting factor they apply to cyclic/volumetric strain based on re-evaluation of a database of case histories. This factor may be reasonably applied within this method of analysis (with consideration of the limitations of the case history database), but it should NOT be applied to other published methods of analysis.
- Jennifer Thornburg, CGS
 Subject : Re:Liquefaction Settlement & Clay Crust.. 08/06/2020 02:46:59 PM 
Donald Cords
Posts: 1
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Jennifer:

Could you please provide some clarification on your assessment of the use of the depth-weighting factor (DF) as proposed in the 2009 Cetin et. al. paper that you referenced? You noted that the method was "reasonably applied" within the limits of the paper but should not be applied to other published methods of analysis.

In the 2009 paper, the authors analyzed liquefaction-induced reconsolidation settlements using methods proposed by Tokimatsu and Seed (1984), Ishihara and Yoshimine (1992), Shamoto et. al. (1998), and Wu and Seed (2004). Are you saying that the use of the depth-weighting factor may be reasonably applied for these methods but that DF should not be used with other methods such as Idriss and Boulanger (2008/2014) or Robertson (2009). Do you have any suggested references that show the use of DF within these methods of analysis is not considered suitable or acceptable?

Don Cords, Geotechnical Professionals Inc.
 
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