Ashburton Reservoir – Support of Excavation Design

The Ashburton Reservoir tanks project is part of an effort by the Baltimore City Department of Public Works (DPW) to convert the city’s open-air drinking water reservoirs to buried tanks in compliance with the federal Safe Drinking Water Act, similar to other ongoing FTG-involved projects at Guilford and Druid Lake reservoirs.

In addition to the installation and management of site geotechnical instrumentation & monitoring, FTG’s team of engineers created a soil nail design for the support of excavation of various below grade structures adjacent to tank construction.

Design challenges included a mix of soil and rock formations, high groundwater levels, avoidance of existing utilities, adjacent structures within zone of influence, and mobilizing available installation equipment.

Construction of the soil nail walls are expected to begin in Spring of 2020. SOE installations will be verified through shotcrete face panel testing and proof load testing of the soil nails. Excavation walls will be fitted with structural monitoring points to be included in the existing site instrumentation program to monitor wall lateral movement and settlement.