Editorial Note - Vol. 9, No. 1, 2015-Article

Article

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This issue of the <em>DFI Journal</em> presents research on geotechnical testing, design practice, inspection tools, and ground improvement. Race and Coffman report full-scale drilled-shaft tests in limestone, using results from three instrumented specimens to develop t–z relationships and offer design recommendations. Fellenius examines residual loads in static pile tests, showing that incorrect assumptions can overestimate shaft friction and underestimate toe capacity.

A survey by Clemence and Lutenegger, conducted with DFI’s Helical Pile and Tieback Committee, finds improved documentation and sharing of installation measurements, particularly torque data. It also identifies a need for more large-scale testing, especially under lateral loads. Ding and colleagues describe a device for measuring sediment at the bottom of drilled shafts without entering the excavation. Laboratory and field trials show promise, while highlighting the need to adapt the device for coarse bottom materials and gather data across more soil types.

Duraisamy, runner-up in the 2014 DFI student research competition, investigates bio-cemented sand through physical modeling and triaxial tests. The work explores the technique’s potential and challenges, and calls for further research before its use in deep soil mixing can be evaluated reliably.

The editors also designate a 2014 “Editor’s Choice” paper: an overview by Olgun and McCartney on thermo-active geotechnical systems. It summarizes an international workshop, reviews design methods, material characterization, and field measurements, and introduces a special issue on the topic.

Keywords

geotechnical testing

drilled-shaft tests

limestone

pile design

residual loads

shaft friction

toe capacity

helical piles

torque data

ground improvement