ECIS milestone

Los Angeles' East Central Interceptor Sewer (ECIS) reached a milestone at the end of September, when the fourth and final TBM broke through, completing a 5.2km drive. A total of 18.3km has been excavated by the Kenny/Shea/ Traylor/ Frontier-Kemper JV, using four Lovat EPB TBMs, for the Los Angeles' department of public works.

Difficult ground had caused engineers some problems during excavation. As previously reported by T&TI, a number of 'chimneys' opened up underneath the Alameda Rail Corridor – a new Los Angeles to Long Beach link – plus other voids along the tunnel's alignment. Extensive compaction grouting was successfully used to remedy the situation.

EPB excavation was specified by the client, the City of Los Angeles Department of Public Works, to give positive support as the machines passed through lenses of intersecting sand. T&TI was recently told by the project manager, Baron Miya, that this method worked well, and that ground conditioners played an important role in avoiding ground settlement. Some voids, however, occurred during TBM tool changes.

The US$280M project also received a boost from the Los Angeles Regional Water Quality Control Board (RWQCB), which extended a Cease & Desist Order from 31 December 2003 to 31 October 2004. "The RWQCB has closely monitored our progress," the Board of Public Works' president said. "They recognised the challenges and extended the ECIS deadline."