Rig facilitates efficient installation of secant piles

The B400 TRD large-bore, dual rotary-head drilling rig from Casagrande will drill a 75-foot deep, 24- to 42-inch diameter hole in a single pass. Casing and drill tooling are turned in opposite directions using a reverse-circulation system that allows for incredibly efficient installation of secant walls.
Up to 75 feet of drill depth can be achieved with the rig in one stroke. The lower rotary head’s chucking system enables the use of a single piece of casing. Together, these features make possible single-pass drilling and provide unsurpassed productivity.
Speed is independently variable across the entire rpm range of both the upper and lower rotary heads. The full torque of the lower head is delivered to the casing and the full torque of the upper head is delivered to the tooling. The use of independent heads allows the hammer to be retracted or advanced, placing it above or below the casing, as needed.
Counter rotation greatly reduces the strain on tooling, casing and rig. Providing a maximum of 339,400 foot-pounds of torque to the lower rotary head and 82 tons of extraction force for casing removal, the B400 TRD is one of the most powerful rigs available for drilled piles and secant-wall systems.
The B400 TRD is Tier 3 emissions compliant. The 600-horsepower machine has an operating weight of approximately 280,000 pounds and is 105 feet tall in operation. Contractors can choose to outfit the rig with continuous flight augers, down-hole hammer systems, or reverse-circulation drill systems.