Problem description

Due to bug fixes and improvements made in PLAXIS 2D 2016.01 related to the thermal capabilities of the calculation kernel, the results of Tutorials 15 and 16 are slightly altered. However, this change is not yet updated in the PLAXIS 2D 2016 Tutorial Manual to reflect these changes.

Solution

Tutorial 15: Thermal expansion of a navigable lock

In 2016.00, the thermal expansion of water was contributing to the thermal strain of the soil body, which is incorrect:  the displacements are only governed by the thermal expansion of the soil skeleton. The thermal expansion of liquid water plays a role in excess pore pressures and groundwater flow, but not directly in the displacements. See section 2.3 of our document on thermal and coupled THM analysis for more details. The correct results are presented below.

Updated Figure 15.17 for PLAXIS 2D 2016.01

Updated Figure 15.18 for PLAXIS 2D 2016.01

Tutorial 16: Freeze pipes in tunnel construction

Many improvements have been made to the convection-diffusion implementation, in particular in terms of calculation stability and performance. They however bring some slight changes in the results of tutorial 16. They are shown below, and as you can see, they are hardly noticeable.

 

Updated Figure 16.6 for PLAXIS 2D 2016.01

Updated Figure 16.7 for PLAXIS 2D 2016.01

Updated Figure 16.8 for PLAXIS 2D 2016.01

Pro tip

When performing a ground freezing analysis, it is good practice to check that the phase transition from liquid water to ice has been properly triggered. Due to the latent heat kicking in, we should see the temperature plateau characteristic of ground freezing. For this tutorial, when pre-selecting a node in the middle of the model, the temperature versus time plot shows the phase change plateau displayed below:

Pro tip: Temperature vs time shows latent heat plateau