Trenchless excavation construction methods: Classification and evaluation

Traditionally, trenchless excavation construction (TEC) methods have been considered only in congested and critical conditions as an alternative to open cutting. As more utilities are placed underground, the demand for these methods has increased. It is common practice in Japan and in European countries to specify the installation of the complete system by TEC methods. This is a growing trend in the United States. For the project to be designed and constructed with minimal delays and disputes, it is important that the major project decision makers (i.e., owner, regulatory-agency representative, architect/engineer, and contractor) be familiar with the available TEC methods and the basic principles of operation. The purpose of this paper is to present a classification system and a comparative analysis on the specific methods.