This latest release solidifies Seequent's Connected Geotechnical Workflow, reducing the need for duplicate entry of data across several software packages. Other functionality adds more geotechnical capabilities to PLAXIS 2D, 3D and Monopile Designer. Interoperability between PLAXIS 2D and GeoStudio 2D has been added, as well as some smaller workflow improvements. For PLAXIS 3D, rock and mining engineers have the cable element at their disposal, a new UDSM for cyclic loading analysis has been made available for offshore engineering and users can import Leapfrog contact surfaces via Seequent Central.

Import of Leapfrog surfaces from Seequent Central (Technology Preview)

With PLAXIS as part of Seequent, the Bentley Subsurface Company, our products continue to offer much tighter integration to enable a Connected Geotechnical Workflow. With the 2023.2 release the first step of this integration in 3D is through the new Import surfaces from Central option. The full Geotechnical Connected Workflow involves Leapfrog Works, Leapfrog Geo or Leapfrog Energy as a starting point, to create a 3D geological model from the incorporation and interpretation of digital site investigation data.

The 3D geological model and the cross sections can then be published to Seequent's cloud-based visualisation and collaboration solution Seequent Central.

Once the Leapfrog project has been published to Seequent Central, PLAXIS 3D can be used to bring in data from the project. The import of surfaces from Central allows users to pull in the most recent geological contact surfaces and topography from a version-controlled cloud based single source of truth, to use as a basis for the creation of PLAXIS 3D models.

Some Leapfrog models are made on the kilometer scale and the surface meshes contained in such projects, whether it's topography or the surface chronology, can easily contain over 100,000 triangles per surface if not more. These scales and triangle magnitudes are by no means suitable for direct geotechnical analysis. Instead of trying to import all Leapfrog data as is into PLAXIS 3D and then cutting the PLAXIS 3D model data to the size and location project site, it is recommended to perform simplification steps in the Leapfrog project itself. Leapfrog offers all the tools to reduce the mesh density of the surface chronology and to redraw the geological model's boundaries. This can be done by either creating a site-specific geotechnical model from scratch with the available site investigation data or resizing and simplifying a copy of an already defined full-scale Geological Model.

Using these simplification methods helps to optimize the performance during import into PLAXIS 3D, as well as during subsequent intersection and mesh generation and ensures that details irrelevant for the analysis are filtered from the final model.

More on Leapfrog Works, Geo or Energy: https://www.seequent.com/products-solutions/leapfrog-works/
More on Seequent Central: https://www.seequent.com/products-solutions/seequent-central/

Export to GeoStudio 2D and import from GeoStudio 2D (Technology Preview)

As part of the Geotechnical Connected Workflow, users now benefit from a smoother bi-directional transition of geometry between Limit Equilibrium and Finite Element analysis, with new import and export capabilities in PLAXIS 2D, avoiding repetitious and error prone re-entry of model data.

A typical safety analysis based on the shear strength reduction method in PLAXIS 2D, will give the user insight in a single and the most prevalent failure mechanism. Evaluating the same geometry with similar constitutive models inside GeoStudio 2D with the Limit Equilibrium method gives users a roughly similar Factor of Safety. However, in GeoStudio 2D the user also has the freedom to use multiple slip surface search techniques and can control the extent of the slip surface evaluation through the input of entry and exit points on the geometry. This allows the user to investigate additional failure mechanisms at specific locations on the geometry and obtain their Factor of Safety, which are not directly obtained from the finite element analysis. In other cases, depending on the project type and country regulations finite element models are required to be accompanied by the evaluation of the Factor of Safety with the Limit Equilibrium method. So, by enabling the export from PLAXIS 2D to GeoStudio 2D, users can extend their geotechnical analysis with Limit Equilibrium analysis almost seamlessly. The movie below gives a quick overview of the new functionality.

In PLAXIS 2D it works as follows: once the finite element model has been fully defined and optionally calculated, the user can employ the new Export to GeoStudio 2D option and choose which construction stage defined in the PLAXIS 2D model should be exported to GeoStudio 2D for subsequent Limit Equilibrium analysis. The exported model is stored as a *.gsz file and from the Export tool there is an option to immediately launch GeoStudio 2D and open the project, allowing the user to continue right away. The assigned soil or rock materials are also automatically included in case the assigned constitutive models are compatible between the two software packages.

In the other practical situation, a user might have already performed Limit Equilibrium slope stability analysis in GeoStudio 2D and would like to or needs to support that analysis by doing a Finite Element analysis, for example performing a stress-strain or settlement analysis or even considering a fully coupled flow-deformation analysis, to check against certain important design criteria or to adhere to local regulations. With the new Import GeoStudio 2D option in PLAXIS 2D reusing an already defined GeoStudio 2D project almost comes naturally and avoids tedious re-entry of the geometry. This new option is shown in the movie below.

A single GeoStudio project can contain multiple individual 3D and 2D geometries, and each of those geometries are used in a combination of 1 or multiple limit equilibrium slope stability (SLOPE/W), groundwater (SEEP/W) or thermal flow (TEMP/W) analyses. With the new option to import from GeoStudio 2D, users can easily select any of the 2D geometries defined in the *.gsz project file and bring them into PLAXIS 2D. Any soil or rock materials assigned the GeoStudio project are also included if the constitutive models are compatible between the two packages.

Modelling reinforcement with Cable elements

In the latest PLAXIS 3D release, the new cable element and cable material type are introduced. Cables can be used to simulate rock reinforcement like grouted cables or frictional/grouted bolts that work mostly in tension and/or compression.

In previous 3D releases users would rely on the embedded beam structural element and change the embedded beam's behavior to act as "Rock bolt" rather than the default "Pile" behavior to model reinforcement. Since the parameter input of the embedded beam material set is highly tailored to its traditional use as a pile element, this can make it difficult to use it as a reinforcement element. Some capabilities that are relevant to modelling reinforcements are also missing from the embedded beam element. These reasons led to the introduction of the cable element in PLAXIS 2D V22.2, where the material set definition included input of bond stiffness and bond strength parameters in line with rock engineering practice, making it easier to use and calibrate. To follow rock engineering practice and for consistency between 2D and 3D, the cable element is now introduced in PLAXIS 3D. Other capabilities of cables include confining stress dependency and pre-stressing of the element.

Note that while the cable element is available as a new structural element in the general program, it is not available yet inside the Tunnel Designer for reinforcement pattern generation. The polar and rectangular array tools are currently necessary to define cable reinforcement patterns along the underground excavation perimeter as well as along its trajectory.

With the introduction of the cable element in PLAXIS 3D, the name in of the element has also been changed in PLAXIS 2D from "Cable bolt" to "Cable" to make the applications consistent. An example on how to define a cable reinforced underground excavation is shown in the following movie:

Enhancements for Seequent's Geotechnical Connected Workflow

The previous release, PLAXIS 2023.1, enabled a connected geotechnical workflow from Leapfrog to PLAXIS 2D, by introducing the option to import 2D cross-sections from Seequent Central, published by Leapfrog. In this release the import of cross-sections from Central is enhanced by including formation names and colours, allowing easier visual matching and comparison between Leapfrog, Central and PLAXIS 2D. During the import, dummy PLAXIS material sets are created and automatically assigned to their corresponding polygons. These material sets have their material model set to "None", which means that after import the user needs to open each material set and select an appropriate constitutive model. However, since the formation names and colours are included in the defined material set already, it should be more straightforward for the user to choose which constitutive model to select.

After importing a cross-section from Central, the geometry is automatically available as polygons. Depending on the geological model or local site conditions, the imported geometry in PLAXIS 2D may contain various features like very small or thin layers, smaller inclusions like lenses or intrusions, or layers pinching out. Such features may have a negative effect on the generated mesh, for example thin sliver like elements with poor aspect ratio or many small elements and could influence the calculation performance. In some cases, certain features may not be relevant to the geotechnical analysis or there is a need to simplify the model for by merging them. To deal with such features, the Combine-command is introduced in PLAXIS 2D. The Combine-command allows the user to select two or more polygons and merge them into one, enabling the removal of small lenses or thin layers. The selection order of the polygons is respected, allowing the material set assignment, or other polygon-based properties to be carried over correctly. Using the Cut-polygon tool together with the Combine-command enables the user to isolate layer pinch-outs by cutting of the sharp thin edges and absorbing them into the surrounding geometry. With the Combine-command it becomes much easier to work with imported data and optimize the geometry for numerical analysis.

The combination of the above enhancements is shown in the following movie:

Modelling cyclic loading and soil degradation with SANISAND-MS

In today's setting where citizens across the globe are increasingly confronted with the disastrous effects of climate change, the ongoing energy transition is seen as the solution to drastically reduce our dependency on fossil fuels and rely on cleaner forms of energy to reduce the world's carbon footprint to stop or at the minimum slow climate change. Especially the offshore wind industry has seen a sharp uptake in the past years as one of the big sources of clean energy. The number of offshore wind farm projects has been growing, with farms growing bigger in number of turbines, as well as the turbines themselves becoming larger and more powerful. With the sheer number of turbines, it is without question that there is a growing need to optimise the design and ensure operational safety across the turbine's lifetime to control the costs and guarantee ongoing power generation. For offshore foundations one of the many aspects in the design is modelling their response to cyclic loading. Out at sea, foundations are subject to high intensity seasonal storms, wind loads and sea waves, i.e., cyclic loads which may gradually tilt turbines over the course of years and may eventually lead to their collapse. These effects can be designed against by taking cyclic loading into account in the initial designs of the foundation, but to do so a constitutive model is needed which can properly account for the soil's response, including its gradual degradation from repeated load cycles. By incorporating the degradation effects of soil, more accurate predictions can be done on for example the gradual accumulation of tilt during the turbine's operational lifetime, compared to commonplace monotonic load analysis. To properly model these effects in PLAXIS 3D, the SANISAND-MS model is introduced as a User Defined Soil Model.

SANISAND-MS is a stress ratio controlled, critical state compatible, bounding surface plasticity model formulated to improve the simulation of the drained mechanical response of sands and sandy soils in high-cyclic loading conditions. The model can be used in engineering applications requiring the prediction of strain accumulation under thousands of drained cyclic loadings. SANISAND-MS includes features such as a memory surface subjected to isotropic and kinematic hardening to account for fabric-related effects on the cyclic ratcheting of sands and a kinematic hardening for the yield surface. The model is available as User Defined Soil Model and can be used by either specifying the cyclic loading through a succession of plastic analysis phases, or with cyclic loading applied as a dynamic load multiplier in a Dynamic calculation phase. For both forms of analysis, the calculation will yield similar results, the main difference being that the former takes more time to set-up and the latter takes much less time to set-up, but more time to calculate.

Read here the documentation for more information.

Small enhancements and fixes

• The 2D to 3D converter tool now also converts cable elements
• Changed model name in bbm64.dll from "UnSaturated model" to "Barcelona Basic Model"
• For all structural element types SumPhase displacements now shows the deformation results only since their activation
• Upgraded ReportGenerator to 64 bits to handle bigger reports

Solved known issues

• Fixed incorrect determination of dynamic point load values in axisymmetric models [link]
• Updated Seequent Central interaction .DLL file to 3.0.8 solving OpenSSL vulnerability CVE-2022-4203 [link]

PLAXIS Monopile Designer

Calibration of multiple ground profiles

Create multiple homogeneous profiles, enabling the numerical-based calibration of all relevant geotechnical units in a single project. The new Calibration matrix merges all functionality previously contained in the Soil and Calibration modes into a visual interface, enabling the specification of the calibration space by cross-defining ground profiles and geometry data sets, and the generation, calculation and parameterisation of the PLAXIS 3D calibration models.

Python scripting - Calibration mode

Automate the entire calibration process. All actions in the Calibration mode, including the generation and calculation of calibration models and the parameterisation of numerical-based depth variation functions, are now accessible through the Python scripting interface. It is also possible to include ad hoc modifications by combining calls to the PLAXIS Monopile Designer and the PLAXIS 3D scripting interfaces.

Built-in API p-y curves for rule-based design

Conventional API p-y curves can now be used in rule-based design workflows without the need of importing an input file. Static API RP 2A-WSD (22nd Edition) curves for sands and clays are available in the Analysis mode, which also enables specifying curve parameters using the same interface as for PISA rule-based models.

Small enhancements and fixes

• Added a Results chart for the distributed moment reaction due to vertical shear, m(z).
• Removed the unit transformation for distributed moment curves when exporting to SACS. Units for the distributed moment, m, were changed in SACS 2023.1 from kN·m/cm to kN·m/m. Users of SACS 2023 and earlier versions will need to manually apply the unit transformation. Updating to the latest version of SACS is strongly recommended.
• Fixed the built-in value of Bothkennar Clay's c8 coefficient, from -0.08456 to -0.8456.
• Fixed an issue where the default values of sand parameters in 3D verification models were calculated based on the relative density specified in the General Dunkirk Sand Model, instead of on the mid-layer small-strain shear stiffness.

So, update to our latest editions to benefit from these new features and software improvements using either the CONNECTION Client or by downloading the software yourself today!

Direct downloads and access to full release notes with all added features:

Request a PLAXIS trial license

Categories

Data Management, Retaining Walls, Deep Foundations, Constitutive Modeling / Soil Behavior, Finite Element / Finite Difference

Keywords

PLAXIS, GeoStudio, Seequent, Bentley Systems, Bentley, Leapfrog, Central