ABSTRACT
Railroad crossings cause traffic congestion and accidents. To address these issues, rail and road separation projects are being promoted in Japan. The Roof and Culvert Jacking Method (R & C) is a leading underpass construction technique, with over 400 projects completed. Recently, large 50 m width box culverts have been introduced to accommodate increased urban traffic. However, this has led to challenges, such as the need for excessive jacking force due to high ground friction, which extends construction periods. To solve these problems, this study develops a new friction-reducing material composed of cement improved soil and rigid balls. Additionally, a new simple shear test apparatus is being designed to simulate the stress conditions during construction and evaluate the performance of this friction-reducing material.
