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Indianapolis CSO 034 & 035 Tunnel

Location: Indianapolis, IN
Owner: City of Indianapolis
Completed: December 2007

This project included design of facilities to capture and consolidate two of Indianapolis’ major combined sewer overflows, lower the flood plain, and improve water quality on the East Side of Downtown Indianapolis. Super Excavators installed 1,640 lineal feet of 167″ OD Reinforced Concrete segments with a finished 12’ inside diameter. The tunnel was constructed using a LOVAT 167SE, 167” diameter EPB TBM. The launch shaft was 69-feet deep and the receiving pits were 40-feet deep. The soils varied from coarse sands to stiff clays. The tie-in to Pogues run required demolition of the existing box culvert, installation of a wet well leading to the new tunnel, and reconstruction of the box culvert to accommodate an overflow rain event. The structural concrete on the project was extensive and difficult due to the high ground water table. This tunnel crossed under two of Indianapolis’ main East-West corridors. We had great success in preventing settlements given the shallow cover of the tunnel and the sandy soils.