CONSTRUCTION OF NATM TUNNEL CROSSING RIGHT UNDER EXISTING RAILWAY TUNNEL

Abstract

This paper reports on the construction of NATM tunnel crossing right under the existing railway tunnel on JR touhoku line.
For operating JR Touhoku line safety, we are measuring the displasement of tunnel profile, joint of lining concrete and axial stress of rock bolt during excavating new tunnel. The measurement have been controlled by limiting value determined by FEM analysis, etc. The railway tunnel does not displace harmufly now. We continue measuring on the consutruction and feed back the result of measurement to construction.