Plaxis Explained

PLAXIS
Developer:	Bentley Systems
Latest Release Version:	CONNECT Edition V20.1 (2D & 3D)
Operating System:	Windows
Language:	English, Chinese, Japanese
Genre:	Computer-aided design, Finite Element Analysis
License:	Floating licensing

Plaxis (sometimes stylised in all caps; Plane strain and axial symmetry, indicating the geometric types handled in the original code^[1]) is a computer program that performs finite element analyses (FEA) within the realm of geotechnical engineering, including deformation, stability and water flow.^[2] The input procedures enable the enhanced output facilities provide a detailed presentation of computational results. PLAXIS enables new users to work with the package after only a few hours of training.

Plaxis BV was acquired by the American Bentley Systems, Inc. in 2018.^[3]

Calculation features

Interfaces

Interfaces^{[4] [5] [6]} these are surfaces along which partial or complete slip of a structure can be simulated using the interaction coefficient, the ratio of friction "soil on soil" to "soil structure"

R _{inter} = (tan \psi)/(tan \phi) . If the interfaces are not marked, the situation of soil destruction is simulated. Recommendation according to Eurocode 0.67. If the resistance parameter Strength is set as Rigid (rigid), this means that there is no separation between the two media and R _{inter} =1 automatically. There is no point in changing the interface in linear models (foundation) (R _{inter} is the coefficient by which we multiply phi and c, which is taken from the nearest soil to reduce contact friction between two different materials). Since there is no strength in the linear model, there is nothing to lower (you can assign R _{inter} in the Mohr-Coulomb model for the foundation R _{inter} =1 ).

An interface is a final element (sonlu eleman) that is responsible for interface elements. Interfaces reduce fi and c near the ground are reduced. Without them, the contact between the pile and the surrounding soil will be absolutely rigid. The soil will remain in one place, the pile will move away. If there are no interfaces, we will supply the soil and the pile will work together. Stress relaxation (when after a week the pile has rested and it is calmly finished off), excess pore pressure will resolve and the pile can be finished off. Viscous soils are modeled by an interface where the phase interface is set to 0.01.

Further reading

• Book: Steinar Nordal. Ronald B.J. Brinkgreve. Present of PLAXIS. Beyond 2000 in Computational Geotechnics. https://books.google.com/books?id=ylNlhdPdB6cC&pg=PA45. 1 January 1999. CRC Press. 978-90-5809-040-9. 45–.

Notes and References

1. Web site: What does PLAXIS stand for?. www.abbreviations.com. March 25, 2023.
2. Book: Chalmovský, Juraj . 2014 . Základy matematického modelování v geotechnice s využitím programu Plaxis . Brno . Vysoké učení technické v Brně, Fakulta stavební . cs. 978-80-214-4938-1.
3. Web site: Bentley Systems Announces Acquisition of Geotechnical Software Leader Plaxis, and Agreement to Acquire Soil Engineering Software Provider SoilVision. 16 June 2022 .
4. Web site: The concept of positive and negative interface . 2022-11-09 . 2022-11-09 . https://web.archive.org/web/20221109161042/https://www.researchgate.net/post/What_is_the_difference_between_a_positive_and_negative_interface_in_plaxis_3d . live .
5. Web site: Plaxis defining Interfaces and finding Riter . 2023-04-17 . 2023-04-17 . https://web.archive.org/web/20230417092856/https://forum.dwg.ru/showthread.php?t=40697 . live .
6. https://www.researchgate.net/publication/322128863_Effect_of_Subsurface_Conditions_on_the_Behavior_of_Footing_by_Using_PLAXIS_Softwar/figures?lo=1 Surface interfaces