Major issues confronting soft-ground tunneling involve the equipment. Owners, the Owner's engineer, the construction contractor, and the tunnel equipment manufacturer have different and often competing interests on a tunnel project. All parties feel they have some stake in what equipment should be used. In current practice, the selection of tunneling equipment is being driven not only by the contractor for considerations of geologic conditions and fundamental constructability, but by Owner and engineer-specified requirements that may be motivated by other factors, such as to reduce risk. A brief history of soft-ground tunneling equipment is presented in order to give a perspective of soft-ground tunneling practices of today. Analysis of past experience and the trends form the basis for presenting the realities of what could, and possibly should, be done in the underground construction industry with regard to tunneling in general and soft-ground tunneling equipment in particular.
