Geotechnical Drilling

Ensure Your Drilling Jobs Run Smoothly

When you’re managing a large construction project, it is important that your geotechnical drilling team completes the job on-schedule. Breakdowns, the wrong equipment, or inexperienced drillers can delay your project and lead to unnecessary expenses. The Gregory Drilling team has a reputation for delivering as promised, even in challenging circumstances. Based on our competitive bidding and reputation for excellent performance, we have been selected for the geotechnical drilling, soil investigating, and installation of monitoring wells for numerous high profile projects.

When it comes to your geotechnical drilling jobs select a team that will help your project run smoothly. Contact the Gregory Drilling team today and put your project in capable hands.

“We depend on accurate, timely information in order to negotiate what are often complex environmental issues. Gregory Drilling enables us to collect the data we need in a timely manner. Their drilling teams are professional, adhere to each job’s unique site requirements, and get the job done right regardless of the challenges. We are consistently pleased with their results and how easy they are to work with. I highly recommend Gregory Drilling.”


Sean W. Donnan, P.G., Principal
Environmental Service Line Director, Western Operating Group
Mountlake Terrace, Washington

Put Reliable Equipment and Experience to Work on Your Jobs

Your geotechnical drilling projects deserve the best equipment and team. With Gregory Drilling, you have reliable equipment, capabilities, and experienced drillers working for you.

Experience Your Geotechnical Drilling Projects Will Benefit From

  • Central Link Sound Transit: drilled and installed over 100 multi-point extensometers and inclinometers over 300 feet deep. Work included truck-based drilling, track-based drilling, night drilling, and weekend drilling.
  • Alaskan Way Viaduct SR 99: drilled and installed over 180 multi-point extensometers and inclinometers over 300 feet deep. Work included truck-based drilling, track-based drilling, night drilling, and weekend drilling.
  • I-405 Lane Additions: drilled over 70 borings for sub-surface investigations. Work included truck-based drilling, track-based drilling, night drilling, and weekend drilling.
  • Bellingham Port Investigation: work included over 30 borings on land, and over water drilling in the port and settlement lagoons. Required the onsite construction of barges and cranes to place equipment in lagoons. Work included fully trained HAZMAT crews, decon of equipment, and full containment of IDW.
  • Everett I-5 HOV Expansion: eight-month job included drilling and installing monitoring wells; soil investigating; and night, road, truck and track work.
  • Transalta Coal Mine: used Foremost DR-12 dual rotary rig to drill 12 monitoring wells/sites 600 – 700 feet deep.
  • Brightwater Wastewater Treatment Facility: during this seven-month job completed 500+ cores, including coring overburden and PQ coring using several rigs according to the depth of location.
  • Bremerton Naval Base: new pier at the naval base involved over-the-water drilling of 15 holes of 175 feet each using casing advancer drilling. Crews worked 24 hours a day and finished two weeks ahead of schedule!


Equipment and Capabilities Your Drilling Job Will Benefit From


  • Limited access hollow stem auger rig: rubber track-mounted, can fit through a 38 inch wide doorway, has a working height of 12 feet 9 inches
  • CME 85, truck mounted drilling rig
  • CME 75, truck mounted drilling rig
  • CME 55 LCX low clearance, rubber track-mounted hollow stem auger rig
  • Foremost DR-12 truck mounted dual rotary drilling rig
  • Geo-Loop grouter (2)
  • Portadrill 524
  • Several support vehicles for removing cuttings, hauling water, and hauling supplies to and from drill sites


  • Installation of a wide variety of geotechnical instrumentation including piezometers, inclinometers, multi-point array extensometers, vibrating wire piezometers, and strain meters
  • Sampling with SPT, Shelby tube, and Dames and Moore
  • Array of mud shakers and systems from small to large for all project sites
  • Mud rotary, air rotary, casing advancer (HQ and HWT)
  • Core drilling with HQ and PQ
  • Hollow stem auger from 3 ¼ inches to 12 ¼ inches
  • Grout mixing plants
  • Construction site dewatering, including installation of vacuum wellpoint dewatering systems
  • Cathodic protection installations

Contact us today to discuss your geotechnical project with an experienced drilling professional.