TúNEL EMISOR ORIENTE IN MEXICO-THE WORLD’S MOST CHALLENGING EPB SHIELD TUNNELLING PROJECT

摘要

This paper presents the main features and the tunnelling construction challenges of the 62 km Emisor Oriente sewage tunnel, north of Mexico City, one of Mexico’s outstanding strategical projects. Six EPB shields with boring diameters of 8.74 m and 8.93 m will excavate mostly soils with overburdens up to 135 m. The soils comprise very soft settlement prone clays of the Mexico Valley, deep consolidated clayey and sandy sediments with boulders with potential water pressures up to 7 bar. Some stretches will also be excavated in hard basalt rock. Apart from the challenges confronted in the design of the two-pass lining, these conditions represent an extension of the typical application ranges for EPB shields. Therefore, great effort will have to be directed to adequately adjust the operation process technologies, enhance the TBM monitoring and process controlling tools and perform additional measures, aiming to optimise key success factors such as the advance speed, the ground conditioning, the minization of tool wear and the muck transport and disposal.