Create centerline for Structural Forces in Volumes

In order to view the Structural forces in volumes in Output, a centerline is required. A centerline can be created manually by selecting points in the model, by adding a centerline from the tunnel designer or by importing *.otnl, *.tnl or *.json files.

Create centerline manually in Output

In a pop-up window the points to define the centerline can be selected directly in the model. This can be done by using the cursor for the selection and/or manually add the exact coordinates of the points for the centerline. After the last point is added, OK can be clicked to view the forces.
Please note that with this method only straight lines can be created in order to define the centerline.

From tunnel designer

To be able to use the option From tunnel designer a thick lining, first, needs to be defined for the tunnel. This option can be found in the tunnel designer in Input, in the Subsections tab. By adding a thick lining a data.otnl file is directly generated by the Plaxis Input program. This *.otnl file is located in the folder of the current project and contains all information about the centerline.

Afterwards, in Output you can add the centerline following the steps below:

1. Select Structural forces in volumes from Tools menu
2. Click on the downward arrow in Add button
3. Select the option From tunnel designer
4. Click OK to view the Forces

In the case that more that one thick lining is defined, the data.otnl file is overwritten in the project folder when saving. In order to keep both files, you need to manually rename the existing data.otnl file before saving the project.
See below how to import the renamed data.otnl file in Output.

Import *.otnl or *.tnl file

A centerline can also be imported using existing *.otnl files from the current or other projects. The *.otnl files are usually located in the project folder of an existing model or stored in a local folder specified by the user.
To do so:

1. Select Structural forces in volumes from the Tools menu
2. Click on the downward arrow in the Add button
3. Select Import…
4. Open the *.otnl or *.tnl file from the location in a windows folder
5. The centerline will be shown as a red line on your model
6. Click OK to view the Forces

Note that a *.tnl file refers to a centerline that was created with PLAXIS 2D AE.00 version, which is currently still supported in PLAXIS 2D.

Import *.json file

JSON (JavaScript Object Notation) is a text format that can be used to generate the points of a centerline.

To create a new *.json file, a simple text file can be created. All relevant information should be added in JSON format and finally the file should be saved using the *.json file extension.

In order to define the points of a centerline, depending on the geometry drawn, a polyline can be used for straight lines and arcs for generating part of an ellipse to form the shape.

Example: polyline

A polyline requires the exact coordinates of each point to be defined.

 

 [{     "type" : "polyline",     "points" : [         [20.25, 11],         [15, 16.25],         [9.75, 11],         [15, 5.75],         [20.25, 11]     ] }]

 

 

 

Example: arc

The arc requires the following parameters to be defined:

• type: arc
• origin: center of the ellipse
• radius0: radius of the ellipse in the x-axis
• radius1: radius of the ellipse in the y-axis (currently radius1 = radius0)
• startangle: counter-clockwise start of the ellipse (from horizontal direction)
• stopangle: counter-clockwise end of the ellipse (from horizontal direction)
• segments: number of generated segments of the arc (more segments will show smoother results)

 [{     "type" : "arc",     "origin" : [15.0, 11],     "radius0" : 5.25,     "radius1" : 5.25,     "startangle" : 90,     "stopangle" : 180,     "segments" : 10 }]

 

 

Example: NATM tunnel

 [{     "type" : "polyline",     "points" : [         [11, 24],         [11, 22],         [14, 22],         [17, 22],         [17, 24]     ]},  {     "type": "arc",     "origin": [14, 24],     "radius0": 3,     "radius1": 3,     "startangle": 0,     "stopangle": 180,     "segments": 36 }]

Please keep in mind that the *.json files should be encoded with ANSI or UTF8-without BOM to be valid for PLAXIS Output.

More information about the JSON format can also be found here:

• http://json.org/
• http://en.wikipedia.org/wiki/JSON