Abstract
The objective of this paper is to provide insight to the application of state-of-the-art ground modification technology for Earth Pressure Balance (EPB) soft ground tunneling. The paper reflects data from a wide array of sources including conference proceedings, trade journal articles, manufacturer publications, books and personal experience. The paper first introduces the concept of soft ground tunneling and then discusses the Earth Pressure Balance Tunnel Boring Machine method. The bulk of the paper is spent discussing ground-conditioning agents, particularly foam. Use of, quantities, theory behind them, environmental impact, lab testing, and effects of foams are described. The paper concludes with a brief case study of the Sheppard Subway Twin Tunnels in Toronto, Canada. Attached to the paper is a comprehensive literature search on EPB tunneling, particularly with regards to foam use.
