Project: Nottingham Cave survey
- Laser scanning
- Confined space survey
- CAD modelling
Our survey team were called in to support the latest stage of an archaeological survey of this ancient cave system under Nottingham city centre.
There are around 500 man-made caves carved into the sandstone beneath Nottingham, dating from the 13th century to the Second World War when they were last dug out to serve as air raid shelters. In the intervening 500 years they have been used as dwellings, beer cellars, cess pits, tanneries, sand mines, kilns and follies.
Our client wanted to know more about the scale and shapes of the caves below the city centre, but confined space and decades of soil seepage from the roof voids had rendered some areas of the cave systems inaccessible to physical investigation.
By necessity this survey was a slow and ongoing operation. We completed three site investigations of the inaccessible spaces using a Cavity Auto- Scanning Laser System (C-ALS) to capture void data. Like a conventional laser scanner, C-ALS uses a laser to record distance and angles to millions of points, but with the added advantage that it can be operated remotely.
The team put together a complex pipe system to feed the laser scanner into the cavern to gather data. Once the laser scan was complete, we returned to the office and converted the point cloud data into 3D CAD models. These models provided a fully imaged representation and measurements of the inaccessible cave structures. They also allowed a specialist archaeological consultant to examine how the cave was constructed, and provided valuable information on the age of the cave system.