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 challengesrnof the 62 km Emisor Oriente sewage tunnel, north of Mexico City, one of Mexico’srnoutstanding strategical projects. Six EPB shields with boring diameters of 8.74 m andrn8.93 m will excavate mostly soils with overburdens up to 135 m. The soils comprise veryrnsoft settlement prone clays of the Mexico Valley, deep consolidated clayey and sandyrnsediments with boulders with potential water pressures up to 7 bar. Some stretchesrnwill also be excavated in hard basalt rock. Apart from the challenges confronted in therndesign of the two-pass lining, these conditions represent an extension of the typicalrnapplication ranges for EPB shields. Therefore, great effort will have to be directed tornadequately adjust the operation process technologies, enhance the TBM monitoringrnand process controlling tools and perform additional measures, aiming to optimise keyrnsuccess factors such as the advance speed, the ground conditioning, the minization ofrntool wear and the muck transport and disposal.