Excavation at Bertha access pit to resume
Dec 16, 2014, 12:48 PM | Updated: Dec 17, 2014, 6:29 am
Crews are allowed to resume excavation on the access pit to stalled tunneling drill Bertha.
The Washington State Department of Transportation stopped crews from drilling at the pit Dec. 12 after about one inch of ground settlement was measured in the surrounding area. However, WSDOT is confident that excavation is not a factor in the settlement. It has not yet confirmed that dewatering efforts are the only contributing factor.
A crack was discovered in the pavement on King Street near 1st Ave. S. Thursday, prompting a temporary road closure. A map detailing the extent of the settlement shows the crack is just above the epicenter of the settling.
WSDOT also said up to 30 buildings are located in the settlement zone. Many businesses in those buildings have reported cracking and shifting.
No significant ground settlement has been observed since Dec. 5, but WSDOT suspended work to give crews time to complete surveys and review Seattle Tunnel Partners’ contingency plan for turning off the dewatering wells.
WSDOT said it’s reviewed the plan, collected more data, and determined recent settlement has stabilized.
