Compressed air use in soft ground tunneling

Compressed air tunneling, used extensively in the past to control ground water and provide face support, is often only given a brief look today because of its escalating cost. However, due to soil and ground-water conditions, the only reasonable way to drive a particular tunnel may be to utilize compressed air. A somewhat complex procedure, the use of compressed air requires a number of precautions to be taken to assure the safety of the work force. Alternative methods or a combination of compressed air and dewatering should be evaluated on a cost-benefit basis.