The Damen Avenue to Roosevelt Road is a $107,000,000 contract consisting of 7,678 m (25,189 Lf) of 9.75 m (32 ft) concrete lined rock tunnel and 27 drop shafts varying-from 1.06 m -7.62 m (3''6" - 25') in diameter, approximately 88.4 m (290 vertical ft) in depth. After the general description of the overall project. a detailed presentation will include a discussion of tunnels and shaft concrete operations and shale conditions at the station tunnel invert. Particular attention will be devoted to the tunnel muck removal system utilizing a vertical conveyor belt. Damen Avenue to Roosevelt Road, the Tunnel and Reservoir Plan (TARP), a Deep Tunnel Project for the metropolitan Sanitary District of Greater Chicago consists of 7677.6 m (25,189 ft) of 9.75 m (32 ft) tunnel with.3 m (1 ft) concrete liner throughout. The 5212 m (17,100 ft) main tunnel connects at both ends with two other Deep Tunnel contracts. A branch tunnel connecting to the mainstream tunnel, commences approximately 1262 m (4140 ft) from the construction shaft and runs 2465.5 m (8089 ft) south and terminates at the Racine Avenue Pumping Station. Shaft work consists of one 8.7m (28' 6") diameter construction shaft, one 1 m (3'' 6") diameter access shaft and 25 drop shafts, four of which have vent shafts. The drop shafts vary in diameter from 1.2 m (4 ft) to 5.2 m (17 ft). All shafts vary in depth to invert from 68.6 - 71.6 m (225 - 235 ft). Work has been underway for 16 months and as of this writing the construction shaft and access shaft are complete. Seven shafts have been excavated and concreting operations have started in four of them. The starter tunnel is complete. the mining machine has mined 76.2 m (250 LF) and the muck removal system is in full operation. The contractor for the project is a joint venture of Paschen/Morrison-Knudsen/Kenny. Paschen Contractors, Inc., Chicago, Illinois is the sponsor. The total contract amount is $107.837, 300.00.
Rock is dolomitic limestone of compressive strengths ranging from 620 - 1172 bar (9000 - 17000 psi). Rock structure is generally bedded with predominantly fine vertical Seams. Brainard formation shale of 276 bar (4000 psi) compressive strengths was encountered at the spring line in the starter tunnel. Although the elevation of shale decreased as the bench of the heading progressed. it did not drop below the invert elevation until approximately 152.4 m (500 LF) of tunnel had been driven. The presence of the shale dictated the need for a.46 m (IS in) mud coat of 276 bar (4000 psi) concrete over the entire starter tunnel floor (10.6 m (35 ft) wide by 174 m (571 ft) long). Problems of air slaking and deterioration under excavation equipment in conjunction with water inflow delayed progress until full round shotcreting and tunnel floor mud coat were completed.
The 9.83 m (32' 3") diameter hard rock tunnel boring machine manufactured by Jarva, Inc., Solon, Ohio, is the second production model of the Mark 30 series to operate in greater Chicago on the Tunnel and Reservoir Plan (TARP) system.