Project Information: Construction of 2,223 m long tunnel, with a cross section between 64 to 75 m2, linking an underground station 120 m long and 172 m2 in section, called Lo Cruzat, with another open-cut station of the same length, called Plaza Qulicura. For the excavation of the tunnel, three circular attack pits of 15 m diameter and about 20 m depth are used. For the excavation of the Plaza Quilicura station, 154 piles D. 1,200 mm, 17 to 24 m deep, are executed. The walls of the excavation are supported by walls between mesh piles and shotcrete with cable anchors of different lengths.