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.