Are you interested in gaining more knowledge about Tunnel modelling in PLAXIS? Are tunnel excavations in rock, NATM, TBM, PLAXIS Tunnel designer of your point of interest? Then this blog is the perfect resource for you to start and explore the PLAXIS tunnelling world.
This blog is a part of the series Tunnel your way to success with PLAXIS. PLAXIS offers a wide range of tools to the Tunnel Engineer, which can be combined to generate almost any ground, tunnel, and reinforcement system geometry. Node-to-node anchorsĀ As their name indicates, node-to-node anchors provide an elastic connection between two non-adjacent nodes. These line elements only interact with the finite element mesh at their end nodes, which makes them especially indicated for modelling the free (unbonded) length of ground reinforcements.Ā Embedded beamsĀ Contrary to the node-to-node anchors, embedded beams areā¦ well, embedded. They are elastically connected to the ground along their whole length, and at the bottom. Thus, they can model almost any reinforcement element: piles and micropiles, dowels, rockbolts, forepoles, etc. They can also be connected to the end of a node-to-node anchor to model the grouted (bonded) partition of any discontinuously coupled reinforcement. Embedded beams cannot be prestressed, but node-to-node anchors can, so their combination can be prestressed through the node-to-node and transmit those stresses to the ground through the embedded beam.Ā Ā Ā CablesĀ If you could mix a node-to-node anchor and an embedded beam, you would get a cable. Cables are line elements that
This blog is a part of the seriesĀ Tunnel your way to success with PLAXIS. Underground construction is a complex endeavour. Leveraging rock masses as engineering materials requires overcoming many challenges. Any work needs to be carried out from within a heterogeneous, often anisotropic medium, with only limited visibility of what lies around. A good understanding of the geology and rock mass characterisation, including fabric and structural discontinuities, is critical.Ā For rock engineers, the ability to tap into connected geotechnical workflows becomes invaluable. The information that you need is likely scattered across multiple systems: geological models, drillhole and core logs, face mapping, laboratory test results, etc. Seequentās suite of solutions provides a connected data environment where geologists and engineers can collaborate to gain an understanding of the underground conditions. This ābig pictureā will then be the main input for all the analyses carried out in the area.Ā Ā Figure 1. Cross-section of an underground mine exported for analysis With PLAXIS, you can accurately simulate the mechanical behaviour of complex rock masses, ranging from massive, blocky to disintegrated or weathered rock. The effect of fabric discontinuities can be captured through equivalent continuum models such as Hoek-Brown with Geological Strength Index (GSI) for isotropic
This blog is a part of the series Tunnel your way to success with PLAXIS. IntroductionĀ This is the second blog covering the modelling of the Traditional Method of Madrid in PLAXIS 2D and 3D. For further details on the method, please refer to the webinar (Traditional Tunnelling Method: Application of MTM with PLAXIS 2D/3D) and blog 1 (PLAXIS 2D – Traditional Tunnelling Method: Application of MTM). In this paper a 3D Approach to Madrid Traditional Method will be presented. However, a 3D model is not always possible due to project constraints, such as budget and deadlines. This paper aims, firstly, to enhance the current design approaches, via a new 2D approach based on a calibration with a 3D SSI model; secondly, to contribute for a more informed design when a 3D model is not available; and thirdly, to contribute to more sustainable designs without compromising safety and quality. SOIL-STRUCTURE INTERACTION Models Ā Firstly, it is necessary to create two models: a three-dimensional and a two-dimensional SSI model, based on the first one. To generate both models, the finite element calculation programme PLAXIS 3D and 2D were used, respectively. The geology for both models is covered in Blog 1 and
This blog is a part of the series Tunnel your way to success with PLAXIS. IntroductionĀ The Traditional Method of Madrid is a method for tunnel construction that has been used for tunnelling in the Madrid Metro network since 1917 (Melis Maynar, M. 2012). The method uses a distinctive excavation sequence that comprises the division of the crown in a series of small excavations that are successively supported by a combination of timber struts, steel waler beams and timber planks during the excavation stage and directly followed by the permanent lining installation. The permanent lining is unreinforced casted concrete (typically C30/37); thus, no reinforcement is normally used. The construction of the walls and invert of the tunnel follow several metres behind, also in the same fashion as an unreinforced concrete permanent liner.Ā The multiple phases and diverse struct distributionĀ of stresses around the tunnel excavation.Ā This article presents the methodology followed for the calibration of bidimensional models of tunnels undertaken by the TMM, via three-dimensional models. Furthermore, it discusses the assumptions and calculation strategies used to achieve an appropriate adjustment that permits the validation of 2D models, which can be used for early stages of a similar project.Ā The Traditional Method
How to Set Up the Fluidity ParameterĀ Ī³Ā of the Hoek-Brown Model with the Softening Model In the framework of numerical analyses of geomaterials, one of the classical problems for modeling the development of shear bands is the pathological mesh-dependence of the computed solution which implies failure without energy dissipation. To avoid this unphysical behavior, an internal length must be introduced to govern the evolution of the shear band thickness in the post-peak regime of the material response. More specifically, it is well known that introducing too large a difference between the dilatancy angle and the equivalent friction angle will lead to a mesh-dependent solution which then will be almost systematically associated with: Numerical convergence difficulties, and Potentially convergence toward an incorrect solution. The numerical solution then becomes ill-posed and the conditioning of the numerical solution further worsen as the difference between the dilatancy angle and the friction angle increases or as the element size in which shear bands develop as a result of shear failure becomes smaller. In this context, the Hoek-Brown with softening (HBS) model uniquely proposes a feature to restore the mesh-objectivity of the numerical solution through a visco-plastic regularization based on the over-stress theory of Perzyna, thus enabling
Durante as chuvas fortes de 2022, uma encosta da PR 182 se rompeu. A estrada Ć© a principal conexĆ£o entre Salgado Filho e Flor da Serra do Sul. Ensolo foi chamada para fazer o projeto de contenĆ§Ć£o dessa encosta para permitir a reconstruĆ§Ć£o desse trecho de rodovia.
An Innovative Project from WSP In the September 3, 2021 issue of New Civil Engineer, an innovative project from WSP is featured: “The addition of yet another high rise development to Londonās skyline is not particularly uncommon. But the construction of the 50 storey Principal Tower, which includes two basement levels, required an innovative engineering approach, as it faced numerous site constraints and the challenge of protecting neighbouring rail assets.Ā Commissioned by a joint venture partnership of developers Brookfield, Concord Pacific and W1 Developments, the buildingās layout features an unusual design, comprising three shapes arranged to make a cruciform measuring less than 25m by 25m.Ā Within the mixed-use building, amenities include a pool, spa, gym, cinema and lounge. The tower is part of the wider Principal Place development, which includes smaller mixed-use buildings and Amazonās new London headquarters.” Read the rest of the article from New Civil Engineer. Read More Gallery With RAM Concept and PLAXIS, WSP created a more efficient design that reduced both material and labor costs. Because of limited space, the GBP 200 million project required a viable design to move forward. Software RAM Concept WithĀ RAM Concept, you can economically design post-tensioned and reinforced concrete floors including
Author: Vincenza Floria and Giuseppe Porcasi, GEODATA GEODATA uses PLAXIS 3D for Cross River Rail tunneling project in Brisbane, Australia