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You are reading the online version of the LimitState:GEO manual, which is also available as a pdf.
Verification
Verification tests
A list of tests carried out using LimitState:GEO to verify its accuracy against known limit analysis solutions may be found at the following web page: http://www.limitstate.com/geo/verification. These tests are run every time the software code is updated, and cover a broad range of problem types such as footings, retaining walls, slopes, and anchors.
Results are presented in terms of deviation from benchmark collapse load and also in
terms of change in input parameters required for the LimitState:GEO solution to match
the benchmark solution. This latter approach matches a design approach that considers
uncertainty in material parameters. It is particulary relevant where the collapse load is a highly
non-linear function of the soil strength. For example a change in 
of 5% can result in a
change of footing bearing capacity by 25% for simple footing problems on cohesionless
soil.
The majority of these tests are carried out using the coarse nodal density. In general, even when using
this coarse density, accuracy in most tests varies from exact to 
5% in terms of the
input parameters. Increased accuracy is straightforwardly achieved by increasing the nodal
density.
An animated image and further details of each test including the source of the benchmark can be obtained by clicking on a hyperlink on the web page. The input file used to generate the test result may also be downloaded.
Academic papers
The following papers may be consulted for comparisons of DLO solutions with known solutions for the listed topics:
- Smith & Gilbert (2007a) Footings on frictional soil, footings on confined layers.
- Smith & Gilbert (2007b) Footings on layered soils, modelling of water pressures in DLO, effect of water table on bearing capacity of footings.
- Smith & Gilbert (2008) Slope stability analysis, footings on slopes.
- Lee et al. (2008) Pipeline bearing capacity.
Other papers that discuss the DLO procedure are listed below:
- Gilbert et al. (2009) Plastic Limit Analysis using Discontinuity Layout Optimization (DLO).