ADOT DS-2 (Drilled Shaft – Gravels and Gravelly Soils)

Document Info

Title: ADOT DS-2 (Drilled Shaft – Gravels and Gravelly Soils)

Authored By: NCS GeoResources, LLC

Report Date: May 2011

Sponsoring Agency: Arizona Department of Transportation (ADOT)



Memorandum DS-2 presents guidance specifically for the design of drilled shafts in gravels and gravelly soils that exhibit drained behavior. Guidance regarding both side resistance and tip resistance is provided. Resistance mobilization curves are presented for gravels and gravelly sands by on work performed by Rollins in Utah and by Arizona Department of Transportation (ADOT). The criterion for “sands” in AASHTO (2010) is also presented to aid in a clear determination of gravels, gravelly soils, and sands within the overall framework of coarse-grained soils exhibiting drained behavior. Clear direction is provided in terms of use of equations to predict nominal resistance in terms of sands, gravels, gravelly sands, and intermediate geomaterials. The guidance in this memorandum was developed with respect to soils in Arizona but most concepts may be generally valid for other regions as well, e.g., definitions for gravels and gravelly sands.


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