The tunnel mould is used for implementing the types of water, sewage, railroad tunnels and others. This mould is produced based on the type of usage of the tunnel in differenet sections such as cricular, horseshoe, elliptical, and semi-circular,...
The tunnel form is formed from two main parts, crust and chariot. Crust has comprised from segments usually with width of 1.5m. Arch Slab mould of the tunnel, crest mould and wall moulds are called as mould petals. The crust us seated on the chariot.
Chariot moves on the rail along with the tunnel and provides the possibility of concreting in the next stages. According to the machanism of opening and closing the tunnel moulds, the tunnel could be divided into two sub-categories:
- Hydraulic Forms
- Mechanical Forms
In the hydraulic forms, the segments of the form or mould are unfolded and folded by using hydraulic jacks and in the mechanical forms they are folded and unfolded by manual or oil jacks. as the segments are heavy, therefore, in the great sections there is used in the legs of the chariot provide the possibility of setting the separating the form after concreting. The hydraulic jacks are also used for folding and unfolding the petals. In the small sections, the mechanical system is used for its economy and confined space.
after any concreting stage, the petals are initially folded by side jacks and then the crust complex will be seat by bare jacks. By moving on the rail, chariot is transferred to its new situation and after lubricating the upper sheet, for facilitating the separation of the mould from the concrete, it will be setup in related height.
The tunnel form must be manufactured such that not losing its efficiency by repeated usage. Other properties of tunnel form include facilitated folding and unfolding as well as longitudinal and transversal displacement.
Selft-traction or mechanical wheels used in the chariot provide the possibility of the movement of the form on the rails and progress of the mould for concreting in the next stage.
The lenght of the mould is mainly 9.6 or 12cm comprised from the connection of segments and chariot by nut and bolt.
The tunnel mould is calculated and designed based on the pressure applied on the wall of the mould based on different conditions such as diameter on the tunnel, thickness of the voncrete, executive limitations, traffic of the vehicles required, form of the section and other factors. By its skilled designing and implementation experts as well as using state of art softare.