The Maryland Transit Administration’s Baltimore Red Line is a proposed 14.1-mile east-west Light Rail Transit (LRT) line connecting the areas of Woodlawn, Edmondson Village, West Baltimore, downtown Baltimore, Inner Harbour East, Fells Point, Canton and the Johns Hopkins Bayview Medical Centre Campus. Red Line has two tunnel segments namely, the Downtown and the Cooks Lane Tunnels. The Cooks Lane Tunnel (CLT) is the shorter of the two tunnels and will connect the proposed at-grade LRT segment running alongside I-70 with the at-grade LRT segment along Edmondson Avenue. The western CLT portal will be west of the intersection of North Forest Park Avenue and Cooks Lane and the eastern portal will be in the median of Edmondson Avenue close to the intersection with Cooks Lane. The length of the CLT is approximately 7,100 feet inclusive of the cut-and-cover and retained cut sections at both ends. The proposed CLT will be excavated below water table and in a variety of ground conditions ranging from soft ground to competent rock. Variable geotechnical conditions, mixed-face tunnel excavation, tunneling adjacent to the existing buildings and utilities, and cut-and-cover construction in urban environment characterize the design challenges of the CLT. This paper presents the design approach for the Preliminary Engineering of the CLT and describes the current proposed design and construction methodology. Different alternatives for the CLT including double-track large-diameter TBM-bored tunnel, single-track twin TBM-bored tunnels, and mined (NATM) tunnel are discussed in this paper. The paper also discusses ground water control during construction, tunnel muck removal, and brief description on numerical modeling and tunnel structural design
