Detecting ground movement and deformation of a large earth retaining structure (landfill)

Detecting and monitoring ground movement and structural deformation in a large earth retaining structure

An earth retaining structure was built following the re-positioning of a stream in a 20 ha landfill site. Fiber-optic sensing cable loops of 2.5 km were installed on geogrids inside the structure to monitor creep and ground movement during and after construction. Strain and temperature were measured with a strain measurement accuracy of 100 με. Measurements over five years showed where strain was occurring and when its evolution slowed down. The system also detected the unpredictable effect of widening an access road to facilitate larger vehicle access.