Development tendencies in mechanised tunnelling - Review and development tendencies for shield machines with slurry and earth pressure support

The demand for efficient tunnels for traffic and utilities is increasing as living space above ground becomes scarce. This requires mechanized tunnelling technology, which sets standards regarding safety, profitability and environmental protection - in traffic tunnelling and in the trenchless construction of utility tunnels such as sewer, water supply, and cable tunnels, or oil and gas pipelines. Different types of machines and working principles have been developed to master the geological and hydrological requirements of tunnelling projects worldwide. Continuous research and development activities have lead to a constant improvement of tunnelling performance; today's TBM technology is therefore capable of handling unstable face conditions with water pressures up to 15 bar. This paper gives an overview of the development steps and of state-of-the-art tunnelling equipment for soft ground application, examines the feasibility of tunnel visions and highlights the innovative and current design approaches for today's specific project requirements.