TECHNICAL | SOFT GROUND TUNNELLING
Other companies involved are:
● Legal: Miranda & Assoc ● Geotech & hydraulics: LNEC ● BIM: ISCTE ● Hydraulics: Hidra/ Engidro ● Project review: IC-FEUP ● Environment: 4 Rs
This ambitious project faces unique challenges due to the complexity of the urban environment. The tunnel boring machine (TBM), a critical component of the project, is now actively engaged in tunnel excavation, being a significant phase in the project’s progression. The TBM is actively excavating the tunnel and
the overall works are being supported by several construction sites across the city, contributing to overall progress. For instance, the excavation work at the tunnel entry point has been completed and the construction location serves as the main hub to support tunnelling activities, including segment supply and spoil removal. Additionally, works are ongoing at the tunnel exit
Above:
Tunnel portal, from where the TBM set off in late 2023
microtunnelling and discharge points (in Parque das
Nacoes and Av. Infante D Henrique), and a survey of the drainage network. Further retention/infiltration basins are planned
for several parks and gardens, such as Parque Oeste, Campo Grande, Quinta da Granja, Vale Fundao, and Vale de Chelas. The focus is the plan is to construct large-scale flow
diversion conduits in the form of two main tunnels in different locations: the approximately 5km-long drainage tunnel extending from Monsanto (inland) down to Santa Apolonia (on the coast); and, the approximately 1km-long tunnel from Chelas (inland) down to Beato (coast). Both tunnels have the same finished diameter of 5.5m
and they are being constructed at average depths of 30m-40m below the ground surface, for much of the alignment except for stretches with cover up to about 70m. The alignment is well below building foundations and transport lines, says the council. Other hydraulic infrastructure in the LDMP design
include retention/infiltration basins and also three shafts with vortices that will be linked to pipes leading into the main tunnels.
MAIN TUNNEL WORKS Following the revitalisation of the project, in 2014, and subsequent approval, in 2015, the procurement process went forward over 2017-18. However, the international open tender process for the design and construction works drew no bids. The process restarted with a call in 2019, award in late 2020, and in early 2021 the city council signed a contract with Mota Engil and Spie Batignolles Internacional. Preparations for the main underground works started in September 2022. Main tunnelling is scheduled to end in 2025. Construction supervision is by the TPF Consortium,
comprising Consultores de Engenharia e Arquitectura S.A and Getinsa Eurostudios, S.L.
24 | November 2024
areas, particularly for constructing the discharge channels to the Tagus River and connecting vortex shafts for surface flow tunnel discharge in city areas periodically prone to flooding. TBM boring has been underway for almost a year
with a CREG machine, manufactured in China. The first task of the 6.41m-diameter earth pressure balance (EPB) machine (ref CTE6410E-1200) is to construct the Monsanto-Santa Apolonia tunnel. Monsanto-Santa Apolonia is the longer of the
two tunnels and is code referenced as TMSA (Tunel Monsanto-Santa Apolonia). It is being bored from its highest point, inland, at Monsanto with the bore on a 0.84% gradient down to Santa Apolonia. Geology is complex. Parts of the machine first arrived from China to
Portugal in late 2022. The TBM - ‘H2OLisboa’ - was launched at the end of 2023 from the Quinta do Ze Pinta site, in Campolide. It has main drive power of 1200kW. By late May, the TBM had advanced almost 550m. Shafts along the downhill alignment of the long
tunnel are at lower points on the ground surface profile - at Av. Da Liberdade, Largo de Santa Marta, and Av. Almirante Reis. The low points will permit drainage collection into the main tunnel during flood operations. Excavation of the shorter tunnel (reference code is
TCB - Tunel Chelas-Beato) is to be undertaken uphill, from Beato to Chelas. The tunnel is to be bored after the TBM first completes the longer tunnel and then the machine will be transferred to Beato for the next main tunnelling task, expected to get underway in late 2025.
CONCLUSION The LDMP exemplifies how innovation and technology can address climate change challenges and promote city sustainability and resilience. By constructing efficient drainage infrastructures and promoting water reuse, the plan contributes to transforming Lisbon into a more resilient and sustainable city.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49
