Excavating a Large-Diameter Tunnel Using the New PLS Method

Hodogaya Tunnel on the New Yokohama Highway

Abstract

The New PLS (Pre-Lining Support) Method was used to widen the Hodogaya Tunnel on the New Yokohama Highway to three lanes along the section of about 200 meters. The greater part of the soil was consolidated silt, on the top of which lay layers of loam and embankments. The overburden was from to 17 meters in thickness. The New PLS Method is a Pre?Lining Support Method, in which the perimeters of the tunnel face is excavated with chain cutter, and immediately reinforced with concrete in the form of ribs to build an arched shell. In this paper, it is describes that New PLS Method, quick hardened concrete using this method and site work.