South Hartford Conveyance Tunnel (SHCT), Hartford, CT
Project Value: $279.4 million. Reference: Jim Sullivan, AECOM (860) 383-5316
The South Hartford Conveyance Tunnel project was completed in 2 stages. The project was completed for the Hartford Metropolitan District Commission (MDC) to store and convey combined sewer overflow as part of a long-term control plan to eliminate discharge into local bodies of water during high intensity events. The following represents the scope of work:
56 borings were completed for the project ranging from 50 feet to 300 feet in depth.
26 geotechnical borings were part of the scope that ranged from 230 feet to 300 feet in depth with overburden ranging from 30 feet to 160 feet
- Environmental and continuous sampling was performed in 4 of the borings
- 18 groundwater monitoring wells were set ranging from 20 feet to 300 feet in depth
- Overburden drilling included dealing predominantly with heaving sands while performing standard penetration testing, split spoon sampling, and Shelby tube sampling
- 12 piezometers were installed in the geotechnical borings
- Each piezometer was set with a flush mounted cover and a concrete pad stamped for identification
- Approximately 400 Packer tests were performed
- 3 of the borings were performed at a 20 degree incline
- A total of approximately 3,600 feet of HQ-size rock was cored during the project
- Quality of rock cores obtained required minimal to no preparation by the laboratories to perform designated testing
- A total of approximately 3,200 feet of overburden was drilled and/or sampled
The drilling schedule for this project required the use of up to 2 rigs at one time and lasted approximately 8 months. The drilling program was completed on schedule and under budget.