The geotechnical engineering group posses a number of engineering software including:
ABAQUS - General purpose finite element analysis programme
ABAQUS is a general purpose finite element program designed specifically for advanced engineering analysis. Structures and continua can be modelled. 1D, 2D and 3D dimensional continuum elements are provided, as well as beams, membranes and shells. ABAQUS is a truly modular code: any combination of elements, each with any appropriate material model, can be used in the same analysis. A wide variety of problems may be addressed with the modelling tools available within the program. The coupled pore fluid pressure and effective stress analysis, known as consolidation, is a typical application of ABAQUS program to geotechnical engineering. The problems could be transient or steady-state, linear or non-linear, and the use of plasticity soil models such as Drucher-Prager model, Cap model and Cam-Clay model.
FEM/GEN and FEM/VIEW
FLAC Version 3.3 is a two-dimensional explicit finite difference program for solving mining and geotechnical engineering problems. The two programmes simulate the behaviour of soils, structures built on soil, rock or other materials that may undergone plastic flow when their yield limits are reached. Materials are represented by elements, or zones, which form a grid that is adjusted by the user to fit the shape of the object to be modelled. Each element behaves according to a prescribed linear or non-linear stress/strain law in response to the applied forces or boundary restraints. The material can yield and flow, and the grid can deform in small and large-strain mode and move with the material that is represented. The explicit, Lanrangian calculation scheme and the mix-discretization zoning technique used in FLAC ensure that plastic collapse and flow are modelled accurately. Because no matrices are formed, large two-dimensional calculations can be made without excessive memory requirements. Several built-in constitutive models are available that permit the simulation of highly non-linear, irreversible response representative of geologic, or similar materials. In addition, FLAC contains many special features such as interface elements, groundwater and consolidation models, structural elements, dynamic and visco-elastic (creep) analysis capabilities.
FLAC Version 3.3 also contains the powerful built-in programming language FISH with which the users can write their own functions to extend FLAC's usefulness and even implement their own constitutive models.
FLAC3D Version 1.1 is a three-dimensional programme which extends the analysis capability of FLAC into three dimensions. FLAC3D is designed specifically to operate on IBM-compatible microcomputers. Calculations on realistically sized 3D models in geotechnical engineering problems can be made in a reasonable time period.
This is a computing package developed by Ove Arup Partnership to cover major aspects of structural and geotechnical engineering:
- Oasys AP+ (Reinforced Concrete Element Design and Analysis)
- Oasys GSA (Skeletal Frame models)
- Oasys BEANS (Building Environmental Analysis System)
- Oasys GEO (Geotechnical Application Programs)
The Geotechnical application programs in Oasys GEO are
- FREW for analysis of flexible retaining walls
- STAWAL for study the stability of 'non gravity' retaining walls
- GRETA for study the stability of gravity retaining walls
- ALP for analysis of laterally loaded piles
- VDISP for calculation of the vertical displacement of layered elastic soil under vertical pressure load
- MINLIN for calculation of the elastic vertical and horizontal displacements by Mindlin equations
- SLOPE for two dimensional slope stability analysis
- PILE for calculation of shaft and base capacities and design loads for given pile and soil parameters
- PILSET for calculation of the settlement of a single pile
- DRIVE for one dimensional analysis of pile driving dynamics
- CLOG for computation of consolidation and swelling due to the changes in loads
- SEEP for two dimensional finite element analysis of steady state flow of groundwater
- SAFE for two dimensional finite element, effective stress analysis of geotechnical problems with plastic soil models
Plaxis is a finite element code for 2D plane strain and axi-symmetric modelling of soil and rock behaviour for use on fast personal-computers. The code uses automatic calculation procedures, and interactive menus combined with direct graphical output. The module provides an elastic model, Mohr-Coulomb and modified Cam-Clay constitutive models. All models can deal with drained/undrained and non-porous material behaviour. Higher order 15-noded or 6-noded elements are used to model the geometry. A variety of structural elements exists to model walls, plates, anchors and geotextiles. Interface elements provide a proper soil-structure interaction. Staged construction enables a realistic simulation of the building process. Iterative procedures are used in combination with automatic load stepping. This provides efficient solutions as the user does not need to select suitable load increments.
SAGE CRISP for windows
CRISP (CRItical State soil mechanics Program) is a purpose-written geotechnical finite element programme, operating under Microsoft windows. It was originally developed by research workers at Cambridge University Engineering Department from 1975 onwards. A wide range of constitutive soil models including Cam Clay, Modified Cam Clay and Schofield model, together with some structural and interface elements. The programme is capable of analysing 2D plane strain, axi-symmetric and 3D soil and soil-structural interaction problems. The effective stress principal is an integral part of the programme and so it can perform drained, undrained and fully coupled (Biot) consolidation analyses.
SEEP/W for windows
This is a finite element programme for analysing groundwater seepage and excess pore pressure dissipation problems including simple saturated steady-state flows to sophisticated saturated and unsaturated time-dependent problems. Physical processes such as infiltration of precipitation and migration of a wetting front can also be modelled in confined or unconfined flow in two or three dimensional axisymmetric condition.
This programme uses the limit equilibrium theory to compute the factor safety of soil and rock slopes for a variety of methods:
- Ordinary or Fellenius
- Bishop's simplified
- Janbu's simplified
- Corps of Engineers
- General limit equilibrium
- Finite element stress
Date transfer between SLOPE/W, SEEP/W and other programmes are all possible.
A computer program to perform dynamic response analyses of Sites Under Multi-Directional Earthquake Shaking. The procedure is formulated on the basis of effective stress principle, vectored motion, transient pore fluid movement, and generalised material stiffness; therefore, it is capable of predicting three-directional motions and the pore water pressure build-up and dissipation within the soil deposits. Each soil layer can be individually modelled using either linear elasticity or other built-in non-linear inelastic constitutive models. The current version of the procedure contains three such models. They are
- The bounding surface hypoplasticity model
- The bounding surface clay model
- The reduced-order bounding surface model
These three models were developed to simulate soil behaviour under a variety of loading conditions.
The multi-directional formulation and the use of plasticity models for soil behaviour enable the procedure to handle shear wave and compression wave simultaneously, and to predict not only horizontal motions but also vertical settlement. Certain effects such as the shaking induced lateral stress variation; soil compression and dilation; the existence of an extremely low stiffness of sands upon liquefaction; etc., are included in the formulation.
The Universal Distinct Element Code (UDEC) is a two-dimensional numerical program based on the distinct element method for discontinuum modelling. It simulates the response of discontinuous media (such as a jointed rock mass) subjected to either static or dynamic loading. The discontinuous medium is represented as an assemblage of discrete blocks. The discontinuities are treated as boundary conditions between blocks; large displacements along discontinuities and rotations of blocks are allowed. Individual blocks behave as either rigid or deformable material. Deformable blocks are subdivided into a mesh of finite difference elements, and each element responds according to a prescribed linear or non-linear stress-strain law. The relative motion of the discontinuities is also governed by linear or non-linear force-displacement relations for movement in both the normal and shear directions. UDEC has several built-in material behaviour models, for both the intact blocks and the discontinuities, which permit the simulation of the response representative of discontinuous geological or similar materials. The programme is based on a "Lagrangian" calculation scheme that is well-suited to model the large movements and deformations of a blocky system.
Together with some in-house developed programmes:
- EPTUN - for 2D finite element analysis of tunnels in elasto-plastic soils
- FEM3D - for 3D finite element analysis of excavations in elasto-plastic soils
- MDSAND - for modelling non-associated plastic behaviour of marine soils
- NAILM5 - for analysing 2D soil nailing system in multi-soil layers
- SUMDES - for dynamic ground response analysis
- NATLPG – for analysing 3D pile groups under lateral and torsional loading
In addition, various soil consitutive models are being developed such as:
- reduced-order sand model for ground response analyss
- disturbed state plasticity model for cyclic loading of soil interfaces
- cyclic Brick model for modelling non-linear stress or strain reversal problems
- bimodal soil-water characteristic curves and permeability functions
- coupled air-water flow analysis
- model for flow in cracked solis