C-Tunnel : a Cetu-itech software
C-Tunnel is a product from the new generation of specialist applications developed by itech. Dedicated to the pre-design of underground structures by means of finite element method, C-Tunnel was developed in collaboration with the CETU (French research centre dedicated to the design, construction, maintenance and operational management of road tunnels).

C-Tunnel combines state-of-the-art analysis methods validated by the CETU with a modern graphical user interface characterised by its intuitiveness and its user-friendliness. It integrates all the specific tools necessary to achieve the pre-design of tunnels and to be applicable to as many tunnel geometries and in situ configurations as possible.


Definition of the geometric data and automatic mesh for one of the standard configurations.
   C-TUNNEL : Wizard software for tunnel design

C-Tunnel allows carrying out a tunnel pre-design in an optimized amount of time. This is achieved thanks to an entirely guided and parameterised model generation process, including the use of templates for geometry description and the guided definition of calculation stages.
      Parametric geometry definition,
      Layered soil formations,
      Automatic definition of the steps of the
     calculation
      Top heading and bench excavation,
      Application of groundwater load on
     impermeable lining,
      Parametric study: definition of variation ranges
     for parametric study, eased comparison of
     results, ...
      Calculations with the famous FEM solver
     CESAR from the LCPC.
Wizards: encapsulation of the tunnel engineer expertise

Two wizards have been added to complete C-Tunnel in terms of embedded engineering expertise.

Bolt system wizard : it allows assessing the apparent cohesion increase in the reinforced zone from the mechanical and geometrical properties of the bolt system.

Lining and arch wizard : it allows assessing the mechanical properties of a homogenous support equivalent to a composite structure made of lining and arches.

Lining and arch wizard
  
The Convergence-Confinement module
 
  The “convergence-confinement” module, revisits this well-known mthod in a very didactic module that enables to test very quickly the influence of a parameter.
 
The convergence curve of the soil is assessed by selecting one of the following material behaviour with or without softening:
      Mohr-Coulomb,
      Hoek and Brown.
 
The displacement curve at the time of the support installation is defined from the elastic method (AFTES) or from the similarity principle.

 Based on geometrical data and material properties, the convergence-confinement curves are calculated and plotted in the toolbox. Numerical results are presented:
      Pressures, displacements, confinement loss at
     support installation, at the equilibrium, and without
     support.
      Normal force and normal stress in support at
     equilibrium, …
  


Extract of a report for a plain strain analysis
   An all-inclusive design environment

C-Tunnel unifies the design approach by gathering in a single project file all the necessary analysis steps – wizards.

The generation of a project report provides a clear overview of the design steps.
The project does not need to be complete to allow report generation.
The content of the report includes project assumptions, results consisting of screen captures, all or parts of individual sub-studies…


C-Tunnel: speed, flexibility and security of a parameterized tool for the definition phase of your projects