Guadarrama Tunnel
Madrid, Spain
TBM rock (Double Shield)
Construction method
57,400 m
Excavated length
8.50m/9.51m
Internal Diameter / Excavation
4 TBM
TBM number
922 m (Coverage)
Depth
With a total length of 28.7 km, the twin-bore Guadarrama Tunnel is the longest railway tunnel in Spain and one of the longest in the world. It was also the first tunnel of this scale to be constructed without intermediate access points, presenting a major technical and logistical challenge.
The tunnel reaches a maximum overburden of 992 m beneath Peñalara Peak, while the crossing beneath the River Eresma was completed with a minimum overburden of just 22 m, highlighting the significant variation in ground conditions encountered along the alignment.
Excavation of both bores was carried out primarily through gneiss (62%) and granite (26%), with uniaxial compressive strengths generally exceeding 80 MPa and an average quartz content of 30-35%. The works were undertaken using four double-shield tunnel boring machines (TBMs) with an excavation diameter of 9.51 m.
Production rates were particularly notable, with peak advances of 80 m in a 24-hour period and an average advance rate of 40 m per day. At the same time as excavation progressed, the TBMs installed the permanent lining using segmental rings with an internal diameter of 8.50 m, a length of 1.60 m and a thickness of 32 cm.
To comply with safety requirements, the two bores are connected by emergency cross-passages at 250 m intervals. During construction, additional temporary cross-passages were provided every 1,000 m, ensuring the safety of workers in the event of an emergency.
The project also incorporated an advanced safety system comprising the emergency cross-passages and a large evacuation chamber with capacity for 1,200 people. This facility is equipped with an independent ventilation system capable of supplying fresh air for up to 48 hours in the event of a fire.
Project data
Project data
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