From the magazine, Microtunnelling, Pipe jacking, Tunnelling

5 minutes with Pezzimenti Tunnelbore

The Pezzimenti name has been synonymous with pipeline construction in Australia since 1957 when Giuseppe Pezzimenti began primarily contracting to the Melbourne Metropolitan Board of Works (MMBW) for the construction of backlog sewers. Over the decades, as one of the leading contractors, Pezzimenti have laid thousands of metres of pipe by conventional pot and drive, open cut and tunnel methods.

Realising the need for greater accuracy beyond the available auger-boring machines of the day, in 1986 Giuseppe’s son Aurelio Pezzimenti designed, manufactured and commissioned the first version of the Pezzimenti Laserbore‰ã¢ Microtunnelling System, a laser-guided vacuum-extraction system designed for superior accuracy and reliability.

This was the first ever system of its type in Australia and the success of this development meant that total lines from manhole to manhole could be achieved with pin-point accuracy. This had a profound impact on the pipe laying industry and changed the way pipes were laid in Australia forever.

Today – Continuing to Lead the Industry

Today, having successfully delivered over 2,500 bores Australia-wide using the Pezzimenti Laserbore Microtunnelling System, Pezzimenti Tunnelbore has remained Australia’s premier microtunnelling company.

Based in Sydney, the Pezzimenti Tunnelbore team combine diverse and specialist engineering expertise with decades of microtunnelling experience. The company has worked alongside Australia’s leading infrastructure developers, completing several major infrastructure projects on time and building a reputation for exceeding the expectations of its stakeholders.

A strong focus on safety, environmental factors and continual improvement has seen Pezzimenti Tunnelbore’s technology go from strength-to-strength, and is now capable of delivering microtunnels:

  • Up to 300 m in length in a single drive;
  • In all diameters ranging from 300-3,000 mm;
  • Within +/- 10 mm accuracy up to distances of up to 150 m and +/- 40 mm up to 300 m now being standard achievements;
  • In a wide variety of ground conditions ranging from clay, sandstone and basalt;
  • In two different modes:
  • Pipe-Jacking / Sleeve Boring – all jacking pipes (concrete, GRP and Polycrete);

    Freeboring – in all self-supporting ground, removing the need for expensive encasing pipes;

  • In extremely environmentally sensitive locations, with minimal shaft sizes, typically 2 x 4 m.

Pezzimenti Tunnelbore is committed to providing the highest levels of quality, professionalism and standards of work. Combining its modern fleet of equipment with the company’s extensive experience and technical skills, Pezzimenti Tunnelbore has the capabilities and confidence to offer its clients cutting-edge services and solutions for even the most challenging projects.

When it comes to microtunnelling, you can be sure that Pezzimenti Tunnelbore is continuously breaking new ground.

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A tunnel of success; Pezzimenti Tunnelbore case studies

Concord West

Power distributors Ausgrid needed to cross the Main Northern Railway in New South Wales in two locations in order to extend their network of high voltage feeder lines. The two crossings were approximately 1 km apart and Railcorp required both crossings to be carried out during a weekend rail possession. Railcorp had scheduled a number of weekend possessions at approximately 12 week intervals throughout the year and Ausgrid set the rail crossings to be completed over the weekend Saturday 2 and Sunday 3 March 2013. Ausgrid let the head contract to Dunmain, an accredited Level One Service Provider working in the electrical industry.

Dunmain completed the construction of both shafts ready for the establishment of the microtunnelling equipment on site and for the jacking frames to be concreted in by the Thursday. Due to the close proximity of the rail, only a few metres were drilled prior to the rail shutdown. The remaining works, 48 m of 900 mm and
30 m of 700 mm pipe jacking, were required to be completed during the shutdown, which was scheduled to start at midnight Friday and end midnight Sunday.

Breakthrough of 700 mm microtunnel

The night shift completed eight pipes by noon on Saturday and the next crew another four, achieving breakthrough at 5 pm on Saturday afternoon. The head was removed, rods retracted and the annular space grouted between the pipes and the microtunnel on the Sunday shift. The conduits were inserted and then grout encased on the few days following the weekend.

Breakthrough of 900 mm microtunnel

The 20 pipes were jacked in over the weekend, with work proceeding again on a 24-hour basis. Breakthrough occurred at 10.30 am on the Sunday. The head was removed, rods retracted and the annular space grouted between the pipes and the microtunnel on the Sunday shift during the shutdown as required. The conduits were inserted and then grout encased on the few days following the weekend.

Gosford under line crossing

Ausgrid required a high voltage power cable to cross under the main Northern Railway just north of Gosford, New South Wales, in order to provide an alternate power supply to consumers on the western side of the railway. One of the major facilities requiring the security of an alternative supply was Gosford hospital.

An interstate contractor arrived on site prior to the shutdown but needed to modify equipment before commencing drilling, losing valuable rail shutdown time on the Saturday morning. After 4 m of the total 66 m bore was completed, a mechanical failure of the equipment stopped all drilling on the Saturday morning of the rail shutdown. Pezzimenti Tunnelbore was called in to assist.

At the preparatory site meeting, arrangements were made to modify the shaft. The 10 m shaft was reduced to 6 m to provide working room. A program for completion was also developed.

Ausgrid were hopeful that due to the urgency of the works Railcorp would approve the microtunnelling to be complete under live rail traffic conditions.

Pezzimenti Tunnelbore proposed to work three 12-hour shifts for three consecutive days, a proposal was approved by Railcorp. Microtunnelling commenced by lunchtime on Friday 22 March and breakthrough occurred mid-morning Sunday 24 March 2013.

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