Abstract

Urban congestion is a serious problem in many cities, so the creation of underground space and in particular the development of underground transport is environmentally essential for our future megacities. How can tunnels be built in ground sometimes as soft as toothpaste? What can go wrong? Will buildings above be affected by subsidence? What else is underground already that might get in the way or be adversely affected? Geotechnical engineering – the application of the science of soil mechanics and engineering geology – plays a key role in answering these questions.

The talk will describe the critical importance of geology and the development and application of the latest underground construction techniques. Examples of current and future projects from around the world will demonstrate the size, technical challenges and complexity of modern underground construction. Protection from subsidence is critical and new ways to evaluate how buildings may be affected by tunnelling and deep excavations will be explained. Innovative protective techniques will also be described, including the control of the tilt of Big Ben during tunnelling for London Underground. Novel techniques for monitoring construction using fibre optic technology and wireless sensor networks will be described, illustrated by some recent case histories.