Threading the Eye

0

Jay Dee/Coluccio JV Completes Brightwater Contract

By Jack Burke

The joint venture of Jay Dee, Coluccio and Taisei (JCT) was the general contractor on the Brightwater West project (BT 4 Tunnel) for King County. That project was awarded in late 2006 and NTP was issued on Feb. 20, 2007. The project consisted of a launch shaft at the Point Wells portal, located on the shore of Puget Sound in Shoreline, Wash., and the construction of 21,000 lf of 13 ft ID precast, bolted and gasketed segmentally lined tunnel. The West Tunnel was nearly mined out in January 2010 when the owner, King County, directed the contractor to stop the tunnel advance pending ongoing discussions regarding the completion of the Central Contract’s BT 3 Tunnel. The tunnel advance was stopped in early February about 140 lf west of the Ballinger Way Shaft (BWS), the end point for the BT 4 Tunnel.

The BT 3 Tunnel was under contract with another joint venture, and mining on that tunnel had been stopped since June 2009 due to wear on the rim bar of the TBM. The BT 3 Tunnel was also planned to hole into the Ballinger Way Shaft, from the east side, coming from the Kenmore Portal. The Central Contract TBM had advanced about 10,000 lf of the 20,000 lf BT 3 Tunnel before being stopped.

/**** Advertisement ****/

As of early 2010, King County was faced with a decision to either continue on with the original contractor and the BT 3 TBM, or look for an alternative to complete this section of the BT 3 Tunnel, which by that time was the only portion of the outfall tunnels not mined. One alternative was to have the BT 4 TBM continue on past the Ballinger Way Tunnel, mining from west to east, to complete the BT 3 Tunnel to the stalled BT 3 TBM.

Negotiations between King County and JCT resulted in a cost-plus-fixed-fee type contract with incentives that was substantially below the estimated cost and time to complete the run with the damaged BT 3 TBM. The new contract, the BT 3 Completion Contract, was finalized between Jay Dee and Coluccio as due to prior commitments, Taisei was not able to participate and chose to drop out of the JV. The new joint venture, Jay Dee/Coluccio (JDC), was given notice to proceed (NTP) on April 12, 2010, with a contract value of just under $69 million.

In the time from early February till April 12, JDC had been engaged with the TBM manufacturer, Lovat Inc. of Toronto, Canada (now Caterpillar Tunneling Canada), to devise a plan and cost estimate to revamp the existing BT 4 TBM to contend with the higher ground and water pressures and different soil conditions of the BT 3 Tunnel. Lovat evaluated the existing BT 4 TBM and developed a suitability report that identified the necessary improvements and revisions to the TBM. JDC was also engaged in freezing the launch eye and starter tunnel for the new BT 3 Completion Tunnel for a distance of 100 lf east of the Ballinger Way shaft. Previously, the hole in eye to the west of the shaft was frozen for 50 lf and the TBM had been stopped prior to entering this frozen zone.

After NTP in April, JDC and Lovat began the modifications for the TBM and trailing gear to allow the machine to excavate the BT 3 Tunnel. These modifications included the addition of three sections of trailing gear gantries to accommodate an additional transformer, sump and discharge pumps, cable tray and other gear for the BT 3 Completion Tunnel that would now be driven downhill from the Ballinger Way shaft in west-to-east direction, the opposite direction from the original design. JDC also installed an additional California switch just west of the Ballinger Way shaft and proceeded with refurbishment of the rolling stock and conveyors at the Point Wells portal.

The freeze for the launch eye and starter tunnel to the east of Ballinger Way shaft was completed in early June 2010 and the TBM was advanced into the shaft, holing out on June 18, 2010. The freezing system was in place and continued to freeze the ground to the east while the TBM cutterhead was removed and brought to the surface. Over the next four weeks, JDC rebuilt and strengthened the cutterhead to withstand the higher pressures on the BT 3 Tunnel. For the West Contract, the TBM had been designed in anticipation of ground and water pressures to a maximum of 5 bar (about 72.5 psi). The TBM had been designed for a maximum pressure of 6 bar or 87 psi. To address the conditions expected in the BT 3 Tunnel, it would now have to be re-rated and certified to operate at up to 7.3 bar or 106 psi.

At the same time, the hydraulics and other systems were also rebuilt to higher pressures and generally repaired after the initial 21,000-ft run. The rolling stock was rebuilt and additional locomotives were purchased from Obayashi in Atlanta and shipped to Brookville for rebuilding. While the cutterhead was being rebuilt, the bearing seals were removed and checked for wear, replacing three of four seals in both the inner and outer race of the bearing; minimum wear was detected in the first of each seal group. The cutterhead was replaced on July 30 and the TBM pushed ahead into the launch ring by Aug. 5, to allow replacement of the articulation joint seals.
In order to push the TBM into the launch seal, it was necessary to descommision the freezing system on the BT 3 side of the shaft as of Aug. 2, 2010. At the same time, JDC added an additional 20-ft long section of screw conveyor and an additional guillotine gate on the TBM, again to counter the higher anticipated pressures. After the forward articulation seal was replaced, the TBM was pushed further to the east and the stabilizer fin seals and passive articulation joint seal were also replaced. Then the TBM was pushed ahead again until the tail can was exposed in the shaft.

Once the tail can was in the shaft, the segments were removed, the existing tail seal brushes were removed and the tail can itself was extended another foot to allow a fourth row of tail seal brushes to be installed. All of the grout and tail seal grease tubes also had to be extended and the new tail seal brushes were welded into place. All of this was accomplished by early September, along with upgrades to the shaft conveyors at Point Wells and bracing of the segments through the shaft. By Sept. 13, JDC was making final adjustments in the computer and guidance system in anticipation of mining by Sept. 20. They were also chasing a minor leak in the cutterhead center swivel that appeared to be a loose fitting or some such minor issue.
By Friday, Sept. 17, it became apparent that the minor issue of a leaking fitting on the swivel was much more serious. As a result, the center swivel was removed and sent to Lovat in Toronto for rebuilding. This became even more serious after Lovat disassembled the swivel in the shop and found serious wear, requiring a complete rebuild of the swivel. Through tremendous efforts on the part of Lovat working around the clock, the swivel was returned to Seattle late on the night of Sept. 29, installed and tested the next day to allow JDC to start mining and get the TBM out of the shaft.

By mining out of the Ballinger Way shaft on Sept. 30, 2010, JDC met Milestone 1 under the contract, and earned the incentive payment established by the contract. On Oct. 1 and 2, JDC replaced the full face of cutters with a new dressing, since the old worn cutters had been used to go through the seal and mine the initial few sets east of the shaft. In addition, the shaft seal was grouted solid.

JDC continued mining out of the frozen ground and moving forward to the east until all of the trailing gear was past the shaft. At that time, JDC moved the ventilation system up to the Ballinger Way shaft to provide fresh air to the heading and blowing back toward Point Wells. All muck continued to be transported through the tunnel to Point Wells, where it was removed to the muck bin for storage until it was loaded onto barges and hauled to its final disposal location at the Mats Mats quarry of Cal Portland on the Kitsap Peninsula, near Port Ludlow.

For the month of October 2010, JDC advanced 436 lf because of all the modifications to the tunnel ventilation and the power configuration at the Ballinger site to ensure against power outages, using two sources of commercial power and a generator backup due to the drive being downhill. Beginning in November 2010 and until the one delay for removal of a boulder in May and June of 2011, JDC maintained an average of between 250 to 350 lf per week. The one delay was on May 12, 2011, when in one push crews encountered a boulder that nearly destroyed the cutterhead. This boulder did break up into pieces but those pieces damaged the back of the cutterhead, tearing off the boxes that protect the hydraulic and ground conditioning lines and pushing the center cutter and swivel back into the cutterhead.

This took over three weeks to repair. On June 9, 2011, mining began again with no sign of squeezing or pressure on the TBM. Mining continued at more than 350 lf per week until reaching the “parking station” and milestone for completion of tunneling about 100 ft from the stalled TBM on July 12, 2011. This was 50 days ahead of the target schedule.

JDC then waited until the freeze system installed around the TBM had sufficiently frozen the soil to allow the BT 3 contractor to remove the TBM cutterhead. JDC then filled the gutted shield with concrete. This took several weeks and on Aug. 10 crews began mining the last 50 ft of tunnel to the start of the frozen ground, 50 ft in front of the now abandoned TBM. On Aug. 15 JDC mined through the frozen ground and the aluminum freeze pipes to the face of the concrete plug and removed all the gage cutters from the TBM. On Aug. 16, 2011, at approximately 2:26 p.m., the JDC TBM Elizabeth poked its center cutter into the BT 3 Tunnel as close to dead center as anyone was able to measure. The TBMs were then grouted together by placing a steel bulkhead between the outer skin of Elizabeth and the interior of the BT 3 TBM and grouting the annulus and entrance seal.

JDC then removed its TBM and placed a concrete closure from the 13-ft ID BT 4 Tunnel rings to the BT 3 Tunnel’s 14-ft, 4-in. rings, all in the tunnel as there is no shaft at the connection location. After the connection was installed, JDC began to clean and de-mobe the tunnel from the connection back to Point Wells and then complete the remaining West Contract work that will finish the Brightwater System for King County. This should happen in mid 2012.
Project personnel for JDC includes Greg Hauser (Project Manager), Thomas McMahon (General Superintendent), Gregg Olsen (Project Engineer), Mina Shinouda (Tunnel Engineer), Peter Wang and Will Hodder (Heading Engineers), Martin Valles and Edgar Valles (Walkers), Curtis Roselle (Office Engineer), Rick Sutton (Safety Superintendent), Renee Halley-Hauser (Office Manager), Diana Fleming (Clerk), and Will Yoho (Master Mechanic).

The Project Representative for King County is Judy Cochran. The Resident Engineer is Mike Cole and the Chief Inspector is Ken Rossi both of EPC Consultants. Shift Inspectors are Carl Neagoy of Jacobs Engineering and Stan Burns of King County. John Gidronie is the Design Engineer with Jacobs Associates.

Jack Burke is a tunneling industry expert and a frequent contributor to TBM: Tunnel Business Magazine.

Share.

About Author

Comments are closed.