AN EXPERIMENTAL STUDY ON DEVELOPMENT OF OVAL SECTION TBM

Abstract

An Oval Section TBM (tunnel boring machine) enables excavation of tunnel with elliptical cross section by inclining the cutterhead. It is developed to utilize the proven conventional TBM technology with minimum modifications.
An inclined cutterhead may create a number of new problems, such as inexcavation efficiency and steering, that are unknown in excavation works using a circular TBM. This paper reports on verification tests carried out to examine the extent of such problems using experimental models of the machine in an attempt to confirm the feasibility of the Oval Section TBM.