ASDSO Dam Safety Toolbox

Drilling

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Drill Rig

"Test holes are drilled to obtain representative disturbed and undisturbed samples to:

  • advance and clean holes to specific horizons for logging, sampling, and conducting tests;
  • advance holes to bedrock to delineate rock surface;
  • install piezometers and relief wells."[1]

"Disturbed samples are commonly obtained through the Standard Penetration Test, using a split-spoon sampler. Undisturbed samples are obtained by pushing or coring a tube into in situ soil materials. The most common undisturbed sampling method is the hydraulic pushing of a Shelby tube, which is referred to as a 'push-tube sample'."[1]

"Test holes may be augered by hand, or through powered drill rigs that are mounted on trucks mounted rig, all-terrain rig, all-terrain vehicles, tracks, or on a barge. Selection of drilling methods depends on:

  • access (terrain roughness, space, and height limitations) and noise ordinance;
  • types of tests or samples needed for the investigation and design needs;
  • disposal of drilling fluids and cuttings (contaminated cuttings and groundwater may have to be handled as hazardous waste), lithology (soil type such as sand, clay, and boulders). rock type, and aquifer characteristics (depth to water)."[1]

Drilling Methods

Best Practices Resources

National Engineering Handbook: Chapter 5 - Engineering Geology Logging, Sampling, and Testing (NRCS, 2012)

National Engineering Handbook Chapter 2 - Engineering Geologic Investigations (NRCS, 2012)

Engineering Geology Field Manual 2nd Edition, Volume 2 (USBR, 2001)

Design of Small Dams (USBR, 1987)

Technical Memorandum 8530-2021-13 Concrete and Rock Core Handling Guide (USBR, 2021)

TR-210-60 Earth Dams and Reservoirs (NRCS, 2019)

Guidelines for Drilling and Sampling in Embankment Dams (USBR, 2014)

Drilling in Earth Embankment Dams and Levees (EM 1110-1-1807) (USACE, 2014)

Trainings

On-Demand Webinar: Drilling Plans and Hazard Evaluations for Dams and Levees

On-Demand Webinar: The Practical Use of Geophysics to Assess Dam and Levee Safety



Citations:



Revision ID: 4467
Revision Date: 11/18/2022