NORTH HOLLYWOOD : Soil Sinkage Again Halts Subway Boring

Tunneling on the San Fernando Valley’s first subway project has been delayed again because of soil sinkage far below the surface of the construction project, officials of the Metropolitan Transportation Authority said Tuesday.

Engineers expect to decide today when to resume boring, which has been halted sporadically since the $65.4-million project began Feb. 13.

To date, work on the two-mile Metro Rail subway line from North Hollywood to Universal City has progressed only 200 feet, said Andrea Greene, a spokeswoman for the MTA. She said the delays are expected because engineers are still adjusting equipment and procedures to deal with the peculiarities of the project.

The latest stoppage was called Friday after workers tunneled a 40-foot-long segment of the duct 60 feet below street level, then discovered a one-half inch slouch in the ceiling of the newly bored segment.

The underground sag had no effect on the surface, where some soil movement is expected, Greene said. However, construction specifications permit no sagging in the tunnel ceiling.

Work initially was suspended Feb. 27 when a similar sagging was noted. Work resumed two weeks later, only to be halted again March 16 when the most serious trouble--a five-inch sag in the street surface--emerged at Lankershim Boulevard and Weddington Street.

Greene said work since has progressed “in stops and starts” as experts study the effects of boring on the sandy soil, which she described as “young alluvium” similar to the soil conditions under Hollywood Boulevard where a portion of the street sunk nearly a foot last July.

“We are taking extreme caution because we don’t want another incident like Hollywood,” Greene said.

The planned North Hollywood station on the Metro Rail Red Line, scheduled to open in 2000, is crucial to an ambitious plan to revitalize the community as a major entertainment center of theaters and shops.