Met undertook a railway embankment survey on a number of projects to monitor the embankments stability. This involved a number of survey techniques.
In close co-operation with engineering practices throughout the UK, Met Consultancy Group has undertaken several projects monitoring the stability of railway embankments.
Embankment work can involve several aspects of survey. Land survey techniques can be used to monitor ground movement over a period of time by measuring lateral and height variations against permanent ground markers or anchors. The base measurement can be taken to sub-millimetre accuracy and once established any variation in the embankment stability can be measured over time.
Geophysical techniques can be used to determine the thickness and condition of construction materials. By comparing the depths and condition of ballast along a length of railway embankment, the maintenance history of the track can be established, highlighting possible areas where they may have been stability problems in the past. Condition information obtainable from a track bed survey usually include:
- The location and extent of voiding or cavities that may exist within or beneath the track bed, and
- Moisture variations and the extent of the mixing of the materials at the base of the ballast.
If ground conditions are optimal a geophysical survey can be undertaken to map natural ground interfaces and slip surfaces.