BWARI Tunnel Breaks ThroughOn 25th October, 2006 the Jay Dee-Michels Pipeline Construction-Traylor joint venture broke through on the Big Walnut Augmentation/Rickenbacker Interceptor (BWARI) tunnel project. The event marks the completion of the first phase of tunnelling on the larger project Clean Rivers being undertaken by the City of Columbus in Ohio, USA. The JV utilized a Lovat mixed face earth pressure balance TBM for the construction of the BWARI tunnel. The 4.9 m-diameter EPB TBM RME192SE series 21200 was equipped with variable speed electric drive, a peripheral drive single-stage screw conveyor and a two component grout system. According to the contractor, the TBM and its innovative systems performed with a high degree of reliability throughout the project.The geology along the 6.3 km tunnel alignment consisted of soil deposits characterised as glacial till and glacio-fluvial outwash materials as well as uniform fine sands and man-made fill. The alignment was also characterized by numerous boulders ranging from 30 cm to 1 m diameter. The entire tunnel alignment was below groundwater table with a maximum water height of about 19 m above tunnel invert. Maximum EPB pressure along the alignment was calculated at 3.3 bar. Click us/39. Visit www.lovat.com, www.jdmtjv.com and http://utilities.ci.columbus.oh.us/sewers_drains/bwari.htm 46/06.