Infrastructure development invariably involves construction of excavations in the ground. These may be long and horizontal – tunnels – or short, often wide and vertical – basement excavations or cut-and-cover tunnels. The excavations need to be formed safely, so stability can be an issue, and increasingly there are major concerns about the assessment and control of deformations caused by their construction.
The central theme of research within the Geotechnical Engineering Research Centre at City University is the investigation of ground movements associated with tunnels and deep excavations during the construction process and a major part of the work has been the application of geotechnical centrifuge modelling of these problems. An important feature of the research has been the use of digital image processing techniques that allows overall patterns of ground movements to be determined, enabling centrifuge modelling to progress from a tool for investigating stability mechanisms to one that can give valuable and detailed insight into pre-failure deformations.
The lecture presented examples of research on tunnels and deep excavations focussing on the overall patterns of ground movements caused by these constructions, the interaction of ground movements with nearby structures and how various structural elements effectively control the magnitude and spread of ground movements.