This article describes the construction of a 760m long tunnel, which is a critical section in the last part of the M40 orbital highway around Madrid, Spain. Completion of the motorway was expected by the end of 1995. The tunnel was built for environmental reasons, under Madrid's famous Monte El Pardo national park, to protect it from any construction damage or disruption. A combination of multiple drift New Austrian Tunnelling Method (NATM) work and the Premill method was chosen to control excavation of the two enormous road tunnel tubes completed in July 1995. Each tube accommodates a 15.4m wide roadway, comprising three 3.5m wide high-speed traffic lanes and walkways of widths 2.5m and 1.0m. Each tube has an excavated cross section of 200-215 sq m and a finished internal clearance of 126 sq m. Cut-and-cover was used to build the 450m of tunnel outside the park boundaries. The 310m of bored tunnel under the park has cover between 12m and 30m deep. The excavation, support, and lining of the tubes had nine phases, which proceeded concurrently. Two Premill machines were used (one for each tube); the cutting blade of each is 5m long, and can cut a 30m wide slot. Early strength of the unreinforced shotcrete fill in the Premill slots is vital to the whole Premill method, which is admitted to have its limitations.

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    LONDON,   United Kingdom  EC2A 2HD
  • Authors:
    • Wallis, S
  • Publication Date: 1995-12


  • English

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Filing Info

  • Accession Number: 00723198
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Jul 26 1996 12:00AM