Potomac River Tunnel
Washington DC, Potomac River Tunnel project achieves productivity gains with Conquip’s BulkX.
ContractorCBNA (Civil Building North America) JV for DC Water
LocationWashington DC, USA
The Project
The Potomac River Tunnel (PRT) is the next major phase of the DC Clean Rivers Project. The project consists of a large-diameter deep sewer tunnel, diversion facilities, drop shafts, and support structures to capture flows from existing combined sewer overflows (CSOs) along the Potomac River and convey them to the Blue Plains Advanced Wastewater Treatment Plant for treatment.
The Challenge
The project team was excavating to create eight shafts, which will be formed into outfall locations on the river. They needed to excavate large amounts of muck and spoil at a depth of around 20 metres, before further excavating a layer of hard rock below that.
The project team needed to efficiently remove the material from the bottom of each shaft surface as they dug down in each phase, lift it vertically out with a crane, move it into muck away zones and remove from site with a series of truck movements each day.
The Solution
Conquip manufactured two, 12,000-litre capacity BulkX along with a customised gantry for the muck to be discharged directly into waiting trucks to take away.
The solution has given this project a large capacity, reliable, robust muck away method. The BulkX has increased the rate of excavation and removal of materials from the project site, while improving safety and removing people-plant interface risks.
Results
Each BulkX was filled with muck by the excavator operator, then lifted up from the bottom of the shaft at a depth of around 20 metres, up to the ground level and then that cycle was repeated. Around 14m3 of material was filled every 6-7mins, which equates to around 9 trucks per hour.
Conquip’s BulkX sped up the excavation process and reduced project dig times significantly.
Project feedback
“The biggest benefit of working with Conquip’s BulkX system is they’ve been hands-on in helping us develop and really bring the efficiency to the system – and we’ve also bought things to the table and shown them that has helped with the efficiency too. So it’s been a good collaboration.”
“We actually have the advantage of live loading the truck instead of using the muck bins. So instead of having to drop the material into the muck bin and then reload it with another piece of equipment, we actually cut down on how much staffing we need for that and we get to live load the truck and send them straight away from the job site. The spoil doesn’t have to be double handled – it just saves us so much time and hassle.
“I would always recommend the BulkX system for mucking away. Conquip are very straightforward, trying to engineer for efficiency and make it better once it’s there.”
Tyler Wilt | Site Manager, CBNA