Lattice Girders used in combination with shotcrete support
DSI Underground has been a leader in the development and manufacturing of underground support systems for over 80 years and has been producing lattice girders in the USA since the 1980s.
Lattice girders serve some of the same basic functions in tunneling as steel arch supports. They are part of the temporary lining which initially supports the excavation and, in some cases, are part of the finished lining. Used with the New Austrian Tunneling Method (NATM) of shotcrete application, lattice girder systems offer a very economical alternative to other support methods for a wide variety of ground conditions.
The use of lattice girders should be considered for projects where shotcrete will be used for temporary or permanent support. These include mining through soft ground, mixed face and rock, or tunnels in which widths or heights may vary. Lattice girders are applied equally well to circular and horseshoe shaped excavations, whether driven full face or heading and bench.
Easier to handle
Lattice girders are light and easy to install safely by hand. The use of lattice girders in conjunction with shotcrete reduces material handled in the tunnel. Crew sizes can be reduced because the supports, which are much lighter than conventional steel arches, can be handled easily without special equipment.
The main advantage of the Lattice Girder is its ability in working with shotcrete. It provides a more efficient bond with the shotcrete strength. Because of the open nature of the lattice beam's construction, shotcrete passes through it readily reducing the possibility of unconsolidated shotcrete areas behind the beam. The shotcrete can be applied evenly producing the superior, integral lining.