Lessons Learned: Field Installation of Strain Gages on High-Strength Geotextile

The Cherry Island Landfill (CIL), located in Wilmington, DE, is undergoing a major expansion to increase its service capacity. To increase landfill volume, a mechanically stabilized earth (MSE) wall is being constructed along three sides of the site. Very soft, compressible soils characterize the subsurface conditions, creating the potential for large settlements and widespread slope stability issues. To facilitate strength gain of the foundation soils, the proposed design includes prefabricated, vertical drains (PVDs) and staged construction of the MSE wall. To reduce lateral spreading movements and improve the system's global slope stability, high-strength geotextile has been placed beneath the MSE wall. As a component of the project's instrumentation program, the geotextiles have been instrumented with strain gages to monitor the performance of the reinforcement. This paper discusses the methodology used to install and monitor the strain gages and presents lessons learned from gage performance to date.