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plaxis tutorial Nyaungdon

Project Group: N11

Project Delta, Nyaungdon N11 Plaxis tutorial

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plaxis tutorial Nyaungdon

Hogeschool Rotterdam Academieplein, Waterbouw R.M. Crooij, 0878120

J.Banis, 0861506 E. Prinsen, 0865891

J. Booy, 0880600

WAMDLT01P Mevr. M. Rutten Mevr. A. Mendez

Dhr. K. van der Sand Dhr. E. Schaap

Dhr. J. Lekkerkerk Dhr. W. de Ruijter Dhr. W. Kuppen

Versie 2.1

Rotterdam, 28 januari 2017

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Summary In this tutorial we will learn the government of Myanmar how to design and calculate levee stability by using methods with small-scale interventions. To improve their knowledge about levee stability we will use the design program Plaxis 2D AE. Finally they will be able to compare different situations and demonstrate the difference in stability of the levee system with help of the program Plaxis. Beside of this, for the government of Nyaungdon we will provide a logbook for using Plaxis. The government will be able to design levees for themselves with this tutorial. This will help to protect Nyaungdon against flood events. In the image below the current Levee positions in Nyaungdon are shown.

Figure 1:Current positions of levees in Nyaungdon

Project Delta, Nyaungdon N11 Plaxis tutorial

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Tutorial In this chapter the steps to create a Plaxis levee model will be given. Users can follow these steps to create a Plaxis model. After the tutorial the users should be able to design their ‘own’ levees.

Step 1 The first step is giving the project a name. It’s smart to give different levee sections a tag so it’s easy to find them in the future.

Figure 2: Project name window

Beside a project name, the model also needs different start values. The model should be set on Plane strain with elements on 15-noded, this is in general use for designing levees. Make sure all units are set on the desired outcome values. In the contour table the maximum dimensions can be filled in, these values will give your maximum project dimensions. In de x and y columns the horizontal and vertical maximum dimensions can be determined by the user.

Figure 3: Project properties / model

Project Delta, Nyaungdon N11 Plaxis tutorial

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Step 2 Next step is creating a borehole with the soil materials. In this borehole the depth of the soil and the groundwater level named ‘head’, can be set. There can be made more layers of soil with different types of soil. The soil characteristics are set in different setups, they can be chosen as default or adapted by the user. The local ground parameters must be examined once in the Nyaungdon levee area, so the user can work with the exact data. For now assumptions for ground layers can be made.

Figure 4: Borehole modify soil layers window

When everything is applied in the program a situation similar as below must be the outcome.

Figure 5: Start situation of the underground layer

Project Delta, Nyaungdon N11 Plaxis tutorial

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Step 3 Next step is to create the levee structure on top of the before completed ground layers. Dimensions of the slope can be drawn with the function lines under the header structures.

Figure 6: Dimensions of the levee drawn with the line function

With the function soil polygon you can fill in the soil structure of the levee structure. Different standard soils are given in this menu, as mentioned before.

Figure 7: Levee base structure without soil input

Project Delta, Nyaungdon N11 Plaxis tutorial

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Figure 8: Examples of a parameters tab sheet of the soil window of the soil interfaces set type, parameters can be adjusted by the user to the desired values if the soil parameters doesn’t match their situation.

Levee soil can be chosen with right mouse click and then choose set material for the desired soil.

Figure 9: Material settings for levee structure in drop down menu

Project Delta, Nyaungdon N11 Plaxis tutorial

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Step 4 Generate the model with the mesh function as shown below. With the mesh function the structure will make a total. After this, the levee is ready for the application of water levels and other calculations.

Figure 102: Model mesh start view

Project Delta, Nyaungdon N11 Plaxis tutorial

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Step 5 Create the different water levels per phase. This can be done with the function ‘create water level’. When the function is selected there can be drawn a line that represent the water level in the current phase that you’re working in.

Figure 113: Different water levels for multiple phases

Switch the water level which is relevant for the situation/phase to the global water level. The calculate function will use the global water level for the calculation. PLEASE NOTICE: make sure all other water levels are switched off per phase when not in use.

Figure 124: Global water level for phase 3 as example

Project Delta, Nyaungdon N11 Plaxis tutorial

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Step 6 In the staged construction function, calculate the model. The phases that are marked with a blue button in the left top corner will be calculated. When the button in front of the phase is red, the phase doesn’t work and need some improvements/adjustments. When the phase got a green button the phase works and is calculated.

Figure 13: Staged construction with water level for phase 2

Project Delta, Nyaungdon N11 Plaxis tutorial

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Step 7 With the function view calculate the results of the model are shown. The output shows what happens to the levee for each phase. Plaxis gives a deformation view of the levee, so the user can directly see what happens to the levee. TIP: when the levee deforms, the user can try to improve the levee stability. Several ways to try this out, are:

Improve current soil parameters, make the dike less water-permeable;

Add soil on the inner side of the levee for more counterforce against the water;

Heighten up and make wider the current levee.

Figure 14: Calculation deformation outcome

Project Delta, Nyaungdon N11 Plaxis tutorial

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Conclusion With the help of this tutorial the people in Nyaungdon are able to design their own levees in their hometown. They can model different situations with all sort of different levee characteristics. They can simulate what will happen when the river rises amongst the dike. With Plaxis they can try out some measurements which may be useful to improve the levee stability.