Overview

After nearly four decades of service, the Clintondale Pump Station was experiencing serious problems: its three, 500 horse power pumps had outlived their life, its operations were outdated, maintenance had to be done in confined space, and the lines leading to the facility were severely inadequate to feed the pumps. The Macomb County Public Works Office retained a construction team led by Walsh Construction to construct a facility to meet current and future needs.  Walsh turned to G2 Consulting Group to solve the challenging geotechnical conditions that were threatening construction.

Challenges/Solutions:

•  Extensive underground construction was required to construct the new pump station design, and the team knew that artesian groundwater conditions existed on site.
• Instead of proceeding with the expensive jet grouting originally recommended to address this, G2 designed a depressurization plan to manage artesian groundwater conditions that included temporary earth retention systems and a geotechnical instrumentation monitoring plan to proceed with construction safely.
• Key to this approach was a remote geotechnical instrumentation plan to continuously monitor groundwater pressures within the aquifer around the shafts and settlement within the cohesive soils at different depths to verify anticipated conditions. The use of continuous monitoring proved to be especially beneficial when structural questions arose during demolition and when the site lost power during dewatering.