Drilling
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
- Hand-Auger Borings
- Power-Auger Borings
- Wash Borings
- Continuous Drive Sampling
- Rotary Drilling
- ODEX Casing Advancement System
- Sonic (Vibratory) Drilling
Best Practices Resources
National Engineering Handbook Chapter 2 - Engineering Geologic Investigations (NRCS, 2012)
Design of Small Dams (USBR, 1987)
Technical Release 210-60: Earth Dams and Reservoirs (NRCS, 2019)
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: 5571
Revision Date: 12/14/2022