ABSTRACT
Singapore enjoys a clean and healthy environment today. It is largely because of the comprehensive sewerage infrastructure construction programs implemented in the seventies and through eighties and nineties. Singapore used Earth Pressure Balance Shield tunnelling system for the first time in 1983 to install a 3000 mm diameter effluent outfall pipeline. Singapore also used advanced Slurry Shield tunnelling system in 1982 to install sewers in water charged sandy strata. Since then these shields and micro shields have been used very extensively to install sewers in Singapore.
