Akkerman Inc of Brownsdale, Minnesota manufactures, sells and rents microtunnelling, pipejacking, tunnel boring, guided boring and sliplining equipment.
D H Akkerman designed and built his first boring head and pipejacking system in 1973 and, since then, the company has provided dependable equipment for hundreds of projects.
Akkerman systems are designed to achieve high production in a wide range of soil conditions, installing RCP and FRP jacking pipe, or steel casings and tunnel liner. A team of experienced engineers and knowledgeable field technicians, together with a large parts department, is dedicated to customer service. Akkerman offers standard lines of equipment, and can also design and build to specific project requirements.
Tunnel Boring Machines
While a mobile electric power pack positioned within the TBM is an option, most Akkerman TBMs are hydraulically driven from power packs located in the start shaft. This cancels the need for high voltage electricity in the head, and makes it more economical to change sizes. A major advantage of the Akkerman TBM design is the facility to access the front of the machine for maintenance, and the face of the bore for removal of obstructions.
Akkerman TBMs are articulated and hydraulically steerable in any direction, and line and grade can be maintained accurately using a laser. Gas detection systems are standard, and the operator is positioned where he can best control advance. When pipejacking, the boring head is advanced by cylinders mounted on the jacking frame at the start shaft, which push the pipe forward. For tunnelling, a thrust section is attached to the rear of the TBM to push off the tunnel lining.
Click on photographs to enlarge
Wheel Machines
These range in size from 1,118 mm (44 in) to 4,267 mm (168 in) diameter. They can be equipped with a dirt cutterhead for clay and silty sand, or a carbide cutterhead for soft to medium rock, with sand shelves available for loose, unstable soil. All three systems are interchangeable, and can be changed at the face. A closed face cutterhead with hydraulically operated doors is available as an option for unstable ground conditions.
Excavator Machines
These are equipped with a backhoe mounted within a steerable shield, with a control module and chain drive conveyor. Sand shelves and closeable doors are available as options. The backhoe rotates, allowing it to dig between the sand shelves. Backhoe and controls transfer easily between different sizes of shields. The boom may be extended to dig ahead of the shield, and a mounting bracket for a breaker can be included. The operator controls all functions using joystick and floor pedals.
Conveyors are available in several sizes to maximise the performance for each size of boring head, with belt and screw conveyors to match ground conditions.
Guided Boring
The Akkerman guided boring system installs small diameter pipes with the grade and alignment precision demanded for sewers and water pipes. The GBM 240 machine uses a specially designed theodolite guidance system to install pipes up to 24 in diameter.
An angled pilot head steers the pilot tubes, which are thrust forward from the drive shaft to the reception shaft. A reaming head and auger tubes are then installed behind the pilot tubes, and the pipe follows in.
Case
Studies
Akkerman supplied a model SL24 boring machine
to Nada Pacific for its sanitary contracts in Freemont, California for
installation of 21 in ID Polycrete pipe. The longest push was 463 ft,
and an overall average of 80 ft of pipe was installed each day, bringing
the project in ahead of time and under budget. Elsewhere in California,
the same contractor is having similar success with an Akkerman SL44 machine
installing 36 in ID pipe.
In Evanston, Illinois, as an adjunct to the Chicago TARP project, L J Keefe Company is installing 72 in ID RCP using an Akkerman model 720C tunnelling shield with closed face and 400 t jacking frame. The soft, silty clay is removed using an 18 in-diameter screw into 5 cu yd muck cars. Bentonite is pumped into the annulus to ease the jacking pressures and support the overcut.
In
Cardiff, Wales, an Akkerman 1.78 m diameter manned TBM has been used with
great success by B&W Tunnelling on a major sewerage scheme where the
installation had a remarkably fast setup time and 187 ft was achieved
in a single 12 h shift.
Akkerman Inc, 58256 266th Street, Brownsdale, MN 55918, USA, tel +1 507 567 2261, fax +1 507 567 2605, e-mail akk@akkerman.com, website www.akkerman.com