Finite element analysis
Three finite element packages (ABAQUS, CRISP and SWANDYNE) are used by our members to model various geotechical processes from relatively simple linear analyses to the most challenging non-linear simulations. Designed as a general-purpose simulation tool, ABAQUS can be used to study heat transfer, mass diffusion, soil mechanics and structural problems. These capabilities have allowed a range of soil-structure interaction and environmental processes to be modelled. The inelastic constitutive theory available within the ABAQUS framework for modelling soil mechanics problems is based on the critical state plasticity theory developed at Cambridge University. CRISP was developed at Cambridge University and is currently marketed by Sage CRISP.
SWANDYNE is a unified general purpose finite element program developed by Andrew Chan. This is a 2D program which uses Biot's fully coupled dynamic equation and can simulate static, consolidating and dynamic conditions under drained or undrained conditions. The programme is currently being used to analyse seismic wave propagation through different soil profiles, with comparison being made with centrifuge test results.
One current project using ABAQUS is the analysis of seepage for the development of shape factors for in situ permeability testing. This work is related to the development of a novel in situ permeability measurement technique using the Cambridge self boring pressuremeter.
The behavior of pipelines subjected to lateral and upward loading in sand is also being studied. The NorSand soil model was implemented into ABAQUS to simulate sand behaviour. The analyses were performed to evaluate an ASCE design guideline.
Compensation injections near a segmental tunnel lining using a pressure-controlled method have been modelled and compared with centrifuge tests. The differences in predictions between the Mohr-Coulomb model and critical state model were assessed.
Also, the development of negative skin friction on piles in consolidating soil has been investigated using ABAQUS. Slip at the pile-soil interface was found to be the most important factor in understanding pile behaviour in consolidating ground. Dragload on single piles and group effects on pile groups are over-predicted by existing design methods. Relatively small group effects were predicted by finite element analyses using slip elements on the pile shaft.
Related Research Topics