Inspection and rehabilitation of “Cerro Azul” Tunnel (Ecuador)
Cerro Azul Tunnel is part of the Daule-Peripa transfer, which supplies water to Guayaquil in Ecuador. The tunnel has a length of 6.450 m and was designed to carry a flow of 44 m/s. Its construction was completed in 1996, but in 2005 a collapsed occurred in the central part of it and in 2007 an emergency repair was carried out. In 2012 the Water Secretariat of Ecuador (SENAGUA) decided to undertake the definitive repair of the tunnel and for this, an inspection of the state of the tunnel was carried out, which led to come to the conclusion that it was subjected to a squeezing process, since its construction in 1996. To define the process in the collapsed area of the rehabilitated cavern a back-analysis was performed through a geomechanical 3D model that allowed to reproduce the phenomenon of creep and the correct dimensioning of the support to place. The tunnel repair started in October 2012 and ended in November 2013.