Geotechnical Services Division

Geotechnical Field Exploration Drilling Equipment

The Field Exploration Unit has a wide variety of field exploration drilling equipment to support the geotechnical field investigations that the unit conducts. 

• Truck Mounted Geotechnical Drills

• Track Mounted Geotechnical Drills

• Skid Mounted Geotechnical Drills

• Cone Penetrometer Testing

• Portable Pontoon Barge

Truck Mounted Geotechnical Drills

The Field Exploration Unit  has two truck mounted geotechnical drills, a Longyear BK-81 and a CME - 55.  These truck drills completed the majority of the easy access drilling that is conducted on the highway’s shoulders or traffic lanes, for example.  When needed the drills are capable of accessing more difficult sites with the assistance of their all wheel drives, winches and bulldozers. 

 Track Mounted Geotechnical Drills

The Field Exploration Unit has two CME – 850 track mounted geotechnical drills.  These drills are capable of climbing 60 degree slopes under their own power and even steeper slopes with the assistance of on board cable winches.  The main feature of this drill is it’s low ground pressure that is rated at 2.5 psi for a drill rig that weighs approximately 30,000 pounds when fully tooled.  It is capable of accessing very soft ground and moderate off road terrain.

Skid Mounted Geotechnical Drills

The Field Exploration Unit has three skid mounted Geotechnical drills.  Two are CME-45 and the third is a Burley 4500.  These drills are the equipment that is used for very difficult access.  These drills can be put on any site regardless of the terrain or obstacles.  The CME-45 drills can be skidded by winch, or set on-site with a boom truck.  The Burley 4500 is can be broken down quickly and easily into components weighing less than 1000 pounds and lifted into place with either a boom truck or flown by helicopter.  Once these components are on site the drill can be easily reassembled.

 Cone Penetrometer Testing

The Field Exploration Unit has one dedicated cone penetrometer (CPT) test truck.  The  CPT test truck is a fully enclosed for operations in any weather.    The CPT testing equipment consists of an electronic instrumented cone  assembly, hollow core sounding rods, a 20 ton hydraulic thrust frame and a computer data acquisition/processing  system. The CPT test truck is capable of conventional CPT (measuring tip resistance and sleeve friction), pore pressure dissipation, and seismic shear wave velocity measurements. The CPT test truck is capable of sounding between 300 and 400 feet a day making it a very efficient and cost effective subsurface testing system.    

Portable Pontoon Barge

The Field Exploration Unit is equipped with a portable aluminum pontoon barge used for in water geotechnical investigations.  The barge is transported to the project site in two pieces and assembled on site with a boom truck.  Once the barge is assembled a skid mounted drill and all the support equipment and tools are loaded into the barge.  The barge is then moved to the drilling site with a 16  foot aluminum work skiff.   The barge is equipped with 4 deck  mounted winches that are attached to 650 pound anchors which holds the barge in place while the test hole is advanced.  The Field Exploration Unit does all the test hole drilling for Washington State Ferries as well as all bridge piers in lakes and rivers.