Headrace Tunnel for Los Negros II HPP

Project Information: The work consists of executing the Headrace Tunnel for the Los Negros II HPP. The tunnel is 2,300 m long with a cross-section of 14 m2. The excavation will be carried out by drill and blast in the areas of intact rock and by mechanical equipment in the areas where the quality of the ground is poor, following the construction philosophy of the New Austrian Method. The main support elements to be applied are Swellex rock bolts, shotcrete and reticular trusses.

Country: Costa Rica

Province: Alajuela

Place: Distrito 2º Aguas Claras


  • Sección: 14 m²
  • Longitud: 2,300 m

Overburden: Medium-High

Method of Tunneling:

  • NATM. Conventional methods

Geology and Geotechnical Data:

  • Sandstone, shale, calcarenite and lahars

Tunnel Equipment:

  • Atlas Copco 282 2-boom jumbo
  • Putzmeister 4210 shotcrete robot
  • ST-1030 low-profile loader