ORIGINAL REPORT, 12:47 PM TUESDAY: Just in from WSDOT – it’s “conditionally lifted” the suspension order for its Highway 99 tunnel contractor, and the tunneling machine is digging again. Here’s the announcement:

Seattle Tunnel Partners has received conditional permission to resume tunneling operations on the SR 99 Tunnel Project. STP resumed mining today after WSDOT conditionally lifted the “suspension for cause” that halted mining and barging-related activities last month following two safety incidents.

As part of the conditions for lifting the suspension for cause, STP will be permitted to tunnel forward and install approximately 25 concrete tunnel rings. During this time, they must demonstrate that they have implemented a number of changes to ensure they can safely continue mining. These changes include:

Updated tunnel work and quality plans, including calculations of the amount of soil removed during excavation of each tunnel ring.
Realignment of key personnel within their quality assurance program.
New quality assurance protocols.
New personnel at key positions within the tunneling operation.
Restructured daily tunneling meetings that include additional participants and protocols.

WSDOT made the decision to conditionally lift the suspension for cause after its team of tunneling experts evaluated documentation submitted by STP over the past several weeks. While mining can resume, barging activities are still restricted pending submittal of additional documentation.

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(WSDOT image)

After three weeks of tunnel-machine stopdown, still no restart plan, but WSDOT is just out with another project update, saying that work is about to start to fix pier damage done in the process of barging what was being dug out. Also: No new sinking – instead, some “upward movement”:

Seattle Tunnel Partners is set to repair damage that occurred at Terminal 46 during the Jan. 12 barging incident. STP will remove 22 damaged timber piles from the pier at the northern edge of Terminal 46 and replace them with temporary piles. Work is expected to begin in the coming days and could take up to 10 days to complete, according to STP.

WSDOT and STP continue to work together to address the “suspension for cause” that halted tunneling and barging operations on Jan. 14. STP crews are prepared to remove excavated soil by truck if tunneling resumes before the pier at Terminal 46 is repaired.

You can watch the pier repairs unfold on our construction camera. The labels on the image (above) call out some of the key elements you’ll see in the regularly updated time-lapse images.

Ground monitoring update

It’s been approximately two weeks since Seattle Tunnel Partners turned off the deep dewatering wells that were used to control groundwater near the access pit. There was some upward ground movement in the days following the shut-off, but the movement quickly stabilized. The degree of movement tapers off over several city blocks and is uniform in nature, which poses little to no risk of damage to the Alaskan Way Viaduct or buildings.

Some ground survey points in the vicinity of the pit show as much as 3/5 inch of upward movement since Jan. 22 when STP began turning off the wells. Some of the Alaskan Way Viaduct columns and buildings show similar movement.

STP had additional, shallower dewatering wells in operation during the tunneling machine repair effort. They turned off the final two shallow wells on Thursday evening. STP and WSDOT continue to monitor the ground, buildings, utilities and the viaduct.

When the digging stopped last month, WSDOT says, 1,280 feet of tunneling was complete, of the expected 9,270 feet.

Two weeks after WSDOT told its Highway 99 tunnel contractor to stop digging, it’s still not ready to give the green light for digging to resume, according to this update late today:

Last week, Seattle Tunnel Partners submitted their analysis of recent incidents on the SR 99 Tunnel Project. WSDOT and their tunnel experts determined STP’s analysis did not sufficiently address the cause of these incidents or specify how they would prevent them from occurring in the future.

(WSDOT graphic from January 13th)
WSDOT has notified the contractor that in order to lift the suspension for cause, STP must confirm that:

· The tunneling machine is operating as intended and meets the design-build contract’s technical requirements.

· All necessary training for staff on the tunneling machine is complete.

· The tunneling work plan is updated to address the issues that led to the sinkhole.

· Processes are in place to ensure STP’s tunneling work plan is followed.

· STP updates its quality program to ensure key quality program managers are involved in all tunneling activities.

It is STP’s responsibility to determine how to address these issues and ensure they are in compliance with the technical requirements of the contract. This section of the tunnel drive was designed to be a test section for operation of the tunneling machine. With approximately 250 feet of tunneling prior to reaching the next planned maintenance stop, demonstration of these steps is critical.

No indication of exactly how this is affecting the schedule aside from obviously pushing it back at least two weeks – including the expected Viaduct closure when the tunnel machine goes beneath it, previously expected to happen in March.

Just in, an update from WSDOT, following up on its order last week telling its contractor to stop Highway 99 tunneling because of recent incidents including a sinkhole and trouble with the barge that was receiving excavated material:

Last week, WSDOT notified Seattle Tunnel Partners that they must “suspend for cause” tunneling operations involving the tunneling machine and the loading of barges. WSDOT took this step to ensure STP’s work can proceed safely following recent incidents on the SR 99 Tunnel Project. Safety remains the top priority for the project and we can’t speculate on when tunneling will resume.

In response to the suspension for cause, STP has informed WSDOT they are analyzing the recent incidents and intend to provide follow-up information this week. WSDOT, in consultation with its tunneling experts, will then review the information and determine the appropriate next steps.

STP has notified WSDOT they plan to sequentially turn off the deep dewatering wells soon. These wells, which have been used to control groundwater, were previously scheduled to be shut off when the tunneling machine reaches the next planned maintenance stop. With tunneling operations currently on hold, STP has determined that there is an opportunity to turn off the wells earlier than planned. We will continue to monitor movement of the ground, structures, utilities and the viaduct. Additional information about our ground monitoring program can be found here.

ORIGINAL REPORT, 12:13 PM: Just in from WSDOT:

The Alaskan Way Viaduct Replacement Program (WSDOT) is in the process of notifying Seattle Tunnel Partners to suspend tunneling operations involving the tunnel boring machine, a “Suspension for Cause” in contractual terms, until such time as WSDOT lifts the suspension in writing. We will provide a copy of the letter after it is delivered to STP.

The following is a statement from Secretary of Transportation Lynn Peterson:

“In light of recent incidents on the SR 99 Tunnel Project, WSDOT is notifying the contractor that they must suspend tunneling work for cause. I share the Governor’s concern for public safety and we want to ensure that the contractor has the right protocols in place to proceed with their work safely.

We are asking that the contractor complete root cause analysis and take the appropriate steps to ensure that incidents, such as the sinkhole near the repair pit, do not occur again. STP will not be allowed to resume tunneling until their analysis and work plans meet the satisfaction of our experts.

I want to remind everyone that replacing the viaduct is critical to public safety. We have conducted surveys of the viaduct and no movement has been observed; surveys will continue. The tunneling work must proceed, but it must proceed safely.”

This week alone, besides the 35′ x 20′ x 15′ sinkhole, there also was trouble with the barge being used for excavation spoils. WSDOT stresses, however, that other work – such as the Highway 99 lane closures starting next week for tunnel-related sign installation – goes on. More as we get it. Per WSDOT’s “Follow Bertha” page, as of Tuesday, 1,280 feet of tunneling had been completed, of 9,270 feet in all.

P.S. Checking our archives – available via Google cache until our full site is up – we note that yesterday was the seventh anniversary of the announcement by then-Gov. Gregoire, then-Mayor Nickels, and then-County Executive Sims that a deep-bore tunnel had been chosen to replace the Alaskan Way Viaduct.

4:02 PM UPDATE: As promised, WSDOT has made public the letter sent to Seattle Tunnel Partners. You can read it in its entirety here. Here’s what’s at the heart of it:

WSDOT has determined that STP has failed to correct conditions unsafe for the Project personnel or general public, and failed to comply with Governmental Approvals, Law, or otherwise carry out the requirements of the Contract Documents. Therefore, WSDOT has the authority to suspend work for cause, pursuant to Contract Sections 14.2 (a) and 14.2(b) and Technical Requirements Section 2.52.7.3.5.

On the night of January 12, 2016, a sinkhole was detected over the tunnel. The full extent of ground loss is not yet determined and settlement is increasing. STP has yet to provide a detailed analysis of the cause of the observed ground settlement, or a plan for modifying tunneling operations to ensure positive ground control at all stages of tunneling (TR 2.32), and to prevent settlement outside of tolerance in the future (see TR 2.52).

On Tuesday January 12, 201 6, STP’s barge filling operation resulted in a barge listing beyond STP’s control. As a result the barge was either let go or broke free from the pier, spilling tunnel spoils into Elliott Bay, and drifted out of control damaging both Terminal 46 and Pier 48. These events created an unpermitted spill of material and posed a hazard to project personnel and the public.

WSDOT requests a meeting with STP within 24 hours to address this matter.

4:10 PM: More news today from WSDOT, the day after the Highway 99 tunneling machine had to stop while they sorted out a problem with the barge that was collecting excavation spoils. The barge problem isn’t fixed yet, but they brought in some trucks, and digging resumed. Then came a sinkhole. Here’s the WSDOT update sent this afternoon:

Seattle Tunnel Partners resumed mining Tuesday evening, using trucks to remove excavated material while they continued working to resolve an issue with a soil-removal barge. STP crews resumed excavation at 7 p.m. Tuesday.

(WSDOT graphic)
Approximately two hours later, a sinkhole developed within STP’s work zone near South Main Street, about 35 feet north of the access pit. It is located more than 100 feet south of the cutterhead’s current location, in ground that crews mined through last week. STP filled the sinkhole overnight with 250 cubic yards of concrete.

This section of the tunnel drive is protected by an underground wall built by STP before tunneling. The wall was designed to isolate ground movement and protect the nearby Alaskan Way Viaduct. A manual survey of the viaduct conducted after the sinkhole developed found no movement. WSDOT and STP will continue surveying and monitoring the ground, viaduct, utilities and other structures.

The cause of the sinkhole is still under investigation. STP is analyzing the portion of the tunnel that crews have excavated since mining resumed. There is no indication that any other locations have experienced ground loss.

STP is reviewing their daily operations as a result of this incident. Immediately they will enhance monitoring protocols by requiring crews to manually verify the amount of soil removed during excavation of each ring.

The protocols STP outlined to enhance monitoring were used in the first 1,000 feet of tunneling and WSDOT is disappointed they were not used when STP restarted tunneling in December 2015. STP has several hundred feet of mining before they reach the next planned maintenance stop. Before leaving the maintenance stop, STP’s operational protocols will undergo an additional review by an expert to assure public safety.

STP has temporarily stopped mining to prepare the muck storage pit to receive excavated material. They plan to resume tunneling this week using trucks to remove excavated material. …

Safety remains our top priority as we work to replace the seismically vulnerable Alaskan Way Viaduct. We expect STP to further investigate this incident and take the appropriate corrective action as they continue to build this important project.

ADDED 6:31 PM: We asked WSDOT’s project spokesperson Laura Newborn about the sinkhole’s size: “According to Chris Dixon, the dimensions of the sinkhole were 35 feet long, 20 feet wide and 15 feet deep.”