• Diseño de portales para evitar o reducir el corte en rocas 

      Arias, Mario; Salazar Ferro, Ricardo (Escuela Colombiana de Ingeniería Julio Garavito, 2017)
      Restrictions on topography lead to designs of portals that do not necessarily intersect with the axis of the track at a right angle. The lack of appropriate guidelines in the design for portals and a vague understanding ...