History & brief description:

A Joint Venture of Acciona Infrastructures and Sando Construcciones were awarded the construction of the suburban rail line by AENA. The extension to Malaga airport required an investment of Euro 280 million. The Los Prados-Airport section runs almost entirely below the surface, crossing under the Guadalhorce River and Malaga Airport’s new runway. The name of the tunnel is “Túnel Guadalhorce-Aeropuerto”. It is an electrified double track tunnel and is part of “La línea C-1 de Cercanías Málaga”, between Málaga and Fuengirola.

  • Client and Location: ADIF (Administrador de Infrasrructuras Ferroviarias); Spain
  • Type of tunnel: Railway
  • Ground conditions: Alternating gravel, sand and clay layer
  • Alignment length: 2900m; Depth=15–28m
  • TBM type: Operating thrust=8500–36600kN; Maximum theoretical thrust=83643kN

Design Approach Adopted

  • Design method & standard used: Spanish code EH-91
  • Specified strengths of concrete — compressive and residual tensile:
  • 50 N/mm2, Flexural tensile strength= 5 N/ mm2, Residual Strength= 2.9 N/mm2
  • Inner and outer diameter: ID 8,43 m, OD 9,07m
  • Ring segmentation: 6 segments + 1 trapezoidal key
  • Dimensions of segments: Segment Width: 1,5 m, Thickness: 0.320m,
  • Type of segment reinforcement: Hybrid: macro synthetic fibre & steel bar
  • Quantity of reinforcement per m3 of concrete: 5 kg/ m3 Barchip fibres & 98 kg/ m3 bars

Project Benefits

Use of macro synthetic fibres as non- corrosive reinforcement for:

  • Crack control
  • Reduced concrete cover
  • Minimising spalling in handling and installation
  • Bursting resistance under jacking loads

EPC Synthetic Fibre Reinforcement Replacing Steel in Modern Tunnel Designs