tunnelling-journal (1)
tunnelling-journal (1)
  • Home
  • Print
    • Subscribe
    • Tunnelling Journal
    • Breakthrough
    • ITA Activity Report
    • A&NZ Journal
    • WTC Preview
    • Media Kit
  • Digital
    • Newsletter
    • E-Shots
    • TJ Digital edition
    • Products Page
    • Media Kit
  • Conferences
    • BTS Conference and Exhibition
    • Cutting Edge 2022
  • Buyer’s Guide
  • Events Diary
  • Jobs
  • About Us
  • Contact Us
  • Podcast

Home > Final Túnel Emisor Poniente (TEP) II project breakthrough

Final Túnel Emisor Poniente (TEP) II project breakthrough

Tris Thomas

Written by Tris Thomas on 12/07/2017 in News

Tagged: underground

In June, 2017, a select group of project officials, including Mexico’s President Enrique Peña Nieto, celebrated the breakthrough of an 8.7m diameter Robbins Crossover TBM, marking the completion of the country’s Túnel Emisor Poniente (TEP) II project.

The TBM, known an XRE, a Crossover (X) between Rock (R) and EPB (E) TBMs, navigated fault zones, variable ground, low cover, and more to achieve a national record of 57m in one day as well as maximum rates of 231m in one week and 702m in one month.
“The XRE has a great advantage as it is designed to work in open and/or closed mode (EPB); allowing it to excavate the tunnel either in soil or in rock. We’ve verified that its performance was very efficient,” said Ing. Juan Alberto Herrera Moro y Castillo, TEP II Section Chief for owner CONAGUA, Mexico’s National Water Commission.
The unique machine and its Robbins continuous conveyor system were built on location using Onsite First Time Assembly (OFTA), and designed for a contractor consortium of Aldesem, Proacon, and Recsa. The Robbins XRE TBM featured components like a convertible cutterhead with interchangeable cutting tools, interchangeable TBM belt conveyor and screw conveyor, and multi-speed gearboxes to increase torque for tunneling through difficult ground. “The benefits of the design are in its exceptional thrust power and in the ease of changing the cutterhead torque. This makes the process much easier should the machine become stuck in difficult ground,” said Alberto Martinez, head of the tunneling department for RECSA.
The XRE machine was launched in August 2015 to bore the 5.8km long wastewater tunnel. The machine was set up in a hard rock configuration and mounted with 20-inch diameter disc cutters. Early in 2016 the TBM hit the first of several contact zones, a 30m wide fault of fractured and blocky rock. While the excavation through the contact zone was slow going, progress picked up again in the more competent andesite rock. After an intermediate breakthrough in March 2016 into an 80m deep shaft followed by inspection and maintenance, the TBM continued on.

While boring in fractured andesite rock in autumn 2016, the TBM encountered a naturally occurring cavern believed to be the result of either a rock fall in a transition zone, or an old, underground lake body that had eroded the rock away. The cavern was estimated at 90 cubic meters in size, including about 57 cubic meters of unstable floor area. The TBM was stopped and immediate measures were taken to stabilize the ground in front of the machine with polyurethane foam before filling the cavern with a mixture of pea gravel and grout.

By the end of October 2016, the TBM had reached a final 900m long section of soft ground, where it was converted to EPB mode. In this final reach of tunnel with low cover, the distance from the top of the tunnel to residential home foundations was as low as 4m and the ground had the consistency of reconsolidated soil. In order to stabilize the soft soils and minimize the risk of settlement below the residential area, the tunneling crew drilled from the surface and installed 890 micro-piles at 1m intervals.  “We were able to do this without causing damage to property owned by neighbors in the zone bordering the path of TEP II, or to the road or the urban infrastructure installed in that area,” explained Ing. Francisco Miguel Lopez, Jobsite Manager TEP II for contractor Aldesa.
Now that tunneling is complete, the tunnel will receive a secondary concrete lining of 35cm thickness before going into service. The wastewater tunnel will overhaul the current system in western areas outside of Mexico City and serve to prevent recurrent flooding in Valle Dorado. In particular, the tunnel will benefit the cities of Cuautital Izcalli, Tlalnepantla, and Atizapan de Zaragoza, which altogether are home to 2.1 million inhabitants.

Comments:

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Search

Digital Edition

More Like This

02/09/2022

Green light for tunnelling between The Bays and Sydney CBD

Green light for tunnelling between The Bays and Sydney CBD

Sydney Metro has received the green light for tunnelling between The Bays and Sydney CBD, thus completing plans for the…

03/10/2022

New underground project pioneers renewable energy storage

New underground project pioneers renewable energy storage

The Subspace Energy Hub at the Hagerbach Test Gallery in Switzerland is an ambitious new project which aims to help…

16/12/2022

Surface depression monitored above Snowy 2.0 headrace

Surface depression monitored above Snowy 2.0 headrace

New South Wales’ Snowy 2.0 teams are monitoring a surface depression that has emerged above the project’s 17km long headrace…

  • Contact Us
  • Media Kit
  • Magazine Archive

Newsletter

The latest from the Tunneling Journal direct to your inbox.

Social



Enquiries

TGS Media Ltd
The Old Library
Webster House
Dudley Road
Tunbridge Wells
TN1 1LE
United Kingdom

© Tunnelling Journal. All Rights Reserved. Privacy Policy / Terms & Conditions. Admin

We use cookies to ensure that we give you the best experience on our website. If you continue to use this site we will assume that you are happy with it.OkRead more