MECHANISED TUNNELLING - PROGRESS AND EXPECTATIONS

The article discusses the development of mechanisation in underground excavation work as well as future problems still to be overcome. From the initial development of the soft ground tunnelling shield the excavation process has remained a difficult one to mechanise due to geological conditions encountered. Development of soft ground and rock tunnelling equipment during the 1950s is said to have been retarded due to misapplication of the machines resulting in increased construction costs. It is believed that research in progress will allow more complete geological information to be gathered so that tunnelling can be executed efficiently even through the worst variable conditions. While it is the support system that often determines the average rate of progress, there is a need for a support system providing both immediate ground support and final lining as well as providing flexibility and adaptability in difficult conditions. Although future excavating machines for use in long tunnel construction are likely to be more powerful, heavier and capable of handling any rock conditions, there is a need for lightweight crawler-mounted machines for rock boring in short tunnelling projects. /TRRL/