PLAXIS version 8 Tutorial manual Dynamics manual

1. PLAXIS version 8
Tutorial manual
Dynamics manual
subject of presentation :
Presented By : Hamed Zarei
The names of God

2. Geometry of a tunnel
Material properties
Boundary conditions
Mesh generation
Initial conditions
Calculations
Viewing output results

3. The creation of a geometry model is based on the input of points and lines. This is
done by means of a mouse pointer in the draw area.

4. Tunnel designer with current tunnel model
The tunnel considered has a diameter of 5.3 m
Space between tunnels is 12m
creation of a horseshoe-shaped tunnel

6. Click on the Standard fixities button to apply the appropriate boundary
conditions. In addition to the standard displacement fixities

7. The creation of material data sets is generally done after the input
of boundary conditions. Before the mesh is generated, all material
data sets should have been defined and all clusters and structures
must have an appropriate data set assigned to them.
After the input of boundary conditions, the material properties of
the Rock clusters and other geometry objects are entered in data
sets.

8. Material properties of Rock in the tunnel project
𝜇
E
( 𝐾𝑁
𝑚2)
𝜑
)Degree(
C
( 𝐾𝑁
𝑚2)
γ
( 𝐾𝑁
𝑚3)
0/235 x1054370030

9. 𝜇
𝑊
( 𝐾𝑁
𝑚
𝑚
)
𝐸𝐼
( 𝐾𝑁 𝑚2
𝑚)
𝐸𝐴
( 𝐾𝑁
𝑚)
0/22/317501/728 x 105
Material properties of the Shotcrete
The properties for those Shotcrete are listed in Table

10. ∅
(𝑚𝑚)
𝐸𝐴
( 𝐾𝑁
𝑚)
251/2x 106
Material properties of the Rock bolt

11. In this example the 15-node element is used as the basic
element type.

12. The global coarseness parameter can remain at its default value (Fine).
It can be expected that stress concentrations occur around the tunnel.
Therefore the mesh should be refined in these areas.

13. The first calculation phase is used to excavate the right tunnel and activate
Shotcrete
Select a Plastic calculation using Staged construction
The second calculation phase is a
plastic calculation, Staged
construction.
The second calculation phase is
used to excavate the left tunnel
and activate Shotcrete

14. Start the calculations
Select some characteristic points for load-
displacement curves

15. Standard earthquake boundaries are used at the bottom and at
the right hand boundary to avoid spurious reflections

16. The earthquake is modelled by imposing a prescribed
displacement at the bottom boundary.
Therefore the input value of the horizontal prescribed
displacements is set to 0.01 m. The vertical component of the
prescribed displacement is kept zero
(ux=0.01m and uy=0.00m).

17. Change the Rayleigh damping parameters
α and β to 0.001 and 0.01 respectively

18. Select Dynamic analysis for the calculation type in the
General tab sheet.
Set the Time interval to 0.5 sec in the loading input box

19. In this phase, a vertical harmonic load, with a frequency of
10 Hz and amplitude of 50 kN/m2