embankment

The embankment is 6m high with side slopes of 1 in 2 and a 5m width crest. The ends of the embankment are constructed from reinforced soil to minimize space requirements and access to the crest will be provided via steps. There will be four 18m wide test plots on each face. The central, 36m long, section has been constructed using good compaction control to simulate a newly constructed embankment. The outer test plots (two 18m long sections either side of the central section) have a 'designed' heterogeneous structure, end-tipped to simulate an older embankment. The two 4m wide biological test plots are well compacted and will provide additional duplication for plant studies.

embankment cross section

Baseline data on the construction material will be established by an initial series of laboratory tests to determine the relationship between water content, dry density and suction for different compactive efforts and conditions. Further testing on several occasions after construction will provide data on the spatial and temporal variability of material properties.

Monitoring equipment will be installed in April 2006. All engineering test plots will be densely monitored. Instrumentation consists of: pins installed in survey grids to monitor surface deformation; inclinometers and extensometers for strains within the slope; and spatial arrays of a combination of piezometers and tensiometers with the capability of measuring positive and negative pore pressures; soil water content profile gauges; temperature sensors; theta probes. Non-invasive portable geophysics surveys will be carried out to determine the detailed spatial distribution of surface wetness across plots. Additionally a autonomous GPS device to produce early warning of slope movements within slopes will be implanted for controlled testing.