Project Location: Lafayette, Indiana
Owner: Nanshan America
GC: Goettle Construction
Engineer: LAN Associates
Project Revenue: $155,000.00
Project Start and End Date: July 2013 – September 2013
The Challenge
During construction of facility upgrades at Nanshan Aluminum, water and running sands were entering the excavation through gaps in the secant pile wall. The excess water and running sands could cause major voids under the existing floor of the plant. There are two (2) water tables present on-site and they are separated by a clay layer. The lower water table is under artesian pressure. Griffin had to lower approximately 10 ft. of water but most importantly stop the running sands from entering the 25 x 30 foot (ft.) casting pit that is 45 ft. deep
The Solution
To dewater the excavation to the required drawdown, Griffin used a modular wellpoint system, installing battered wellpoints at an angle, by hand jetting between the gaps in the concrete secant pile walls. Additional locations for wellpoint installation were provided by drilling through the concrete. A supplementary vertical modular pumping system was installed in one corner of the pit with a backup system in the opposite corner. Each modular system had a 15 horsepower (HP) submersible pump that was placed in the vertical can. A vacuum pump was placed on the surface to provide vacuum into the can systems.
The Griffin Difference
Griffin addressed the groundwater issues on-site by designing a wellpoint dewatering system capable of lowering groundwater 10 ft. to safely complete the project and keep the plant foundation secure. Griffin installed the system by working around the clock with two (2) crews. Most importantly, the system eliminated the running sands into the excavation, easing fears of settlement of the existing floor.