For the visualization and analysis of the stress field from 4D thermo-hydro-mechanical (THM) numerical model results two main technical steps are necessary. First, one has to derive from the six independent components of the stress tensor scalar and vector values such as the ori-entation and magnitude of the maximum and minimum horizontal stress, stress ratios, differential stress. It is also of great interest to display e.g. the normal and shear stress with respect to an arbitrarily given surface. Second, an appropriate geometry has to be given such as cross sections, profile e.g. for borehole pathways or surfaces on which the model results and further derived values are interpolated. This includes the three field variables temperature, pore pressure and the displacement vector.

To facilitate and automate these steps the add-on GeoStress for the professional visualization software Tecplot 360 EX has been programmed. Besides the aforementioned values derived from the stress tensor the tool also allows to calculate the values of Coulomb Failure Stress (CFS), Slip and Dilation tendency (ST and DT) and Fracture Potential (FP). GeoStress also estimates kinematic variables such as horizontal slip, dip slip, rake vector of faults that are implemented as contact surfaces in the geomechanical-numerical model as well as the true vertical depth. Furthermore, the add-on can export surfaces and polylines and map on these all available stress values.

The technical report describes the technical details of the visualization tool, its usage and exemplifies its application using the results of a 3D example of a geomechanical-numerical model of the stress field. The numerical solution is achieved with the finite element software Abaqus version 2019. It also presents a number of special features of Tecplot 360 EX in combination with GeoStress that allow a professional and efficient analysis.

Version History - Changes with respect to GeoStress v1.0

Even though the general functions and the graphical user interfaces of GeoStress have not changed at all the technical changes in the background are significant. The three main changes of the new version 2.0 are:

1. Comprehensive re-organization of the GeoStress interpolation scheme for external surfaces and polylines. In GeoStress v1.0 all stress variables are derived from the 3D stress tensor components and then were interpolated on external surfaces and polylines. However, when these variables are bi-polar data, such as the SHmax orientation, the interpolation could have produced wrong results when the orientation was 179°N on one side of the surface and 1°N on the other side. The mean would have been 90°N which is obviously not correct. In GeoStress v2.0 all stress values on external surfaces and polylines are newly derived from the six independent components of the stress tensor. The only performed interpolation is that of the six independent components of the 3D stress tensor on the respective feature.

2. Version 2.0 of the Add-on GeoStress is compatible with the Tecplot 360 EX 2019 R1 version which was released in October 2019. This version can load *.odb files from the Abaqus version 2019. Furthermore, the Tecplot 360 EX 2019 R1 version is significantly faster in loading and processing model results. Furthermore, we now also provide, besides the 64-bit Windows version, a Linux-Version of the Add-on.

3. An additional library to use the functionalities of GeoStress together with Tecplot Macros or PyTecplot. This is of particular interest when large numbers of models have to be analysed automatically without starting the graphical user interface of GeoStress.

We also fixed a few minor bugs in the GeoStress v1.0 manual and polished a few issues on the user interface of GeoStress. Furthermore, we extended the manual with brief descriptions and examples how to use the library GeoStressCmd.dll for Windows with PyTecplot. We also provide with libGeoStressCmd.so a version for Linux operating systems.