Frequently Asked Questions

What is GALENA?
What will GALENA run on, and what will it output to?
What is the advantage of using Bishop's method?
What is the advantage of using Spencer's method?
What is the advantage of using Sarma's method?
How are non-vertical slice boundaries generated when using Sarma's method?
Does GALENA use other methods of analysis, eg. Fellenius, Corps of Engineers, Morgenstern-Price?
How can pore pressures be modelled?
Can pore pressures be simulated by inputting a grid of pore pressures?
Can an increase in strength of clays with depth be simulated?
What is the limit to the number of trial failure surfaces used?
What is the RESTRAINTS command?
What is the BACK ANALYSIS command?
How are GALENA data files generated?
Can output files be generated for use with other packages, and in what formats?
Does GALENA have a hardware security key?
What detailed information is available when using GALENA?
What backup and support is available?
Has GALENA been independently checked by anyone?
Who uses GALENA?

Q. What is GALENA? Back to top of page
A. GALENA is a comprehensive and user-friendly Slope Stability Analysis system written by practising engineers for engineers. GALENA was originally written for mining applications, but has now been widely accepted as a valuable tool for use in civil and geotechnical engineering, and for teaching and research applications as well.

Q. What will GALENA run on, and what will it output to? Back to top of page
A. GALENA is a Windows based program and will run on IBM and IBM compatible PC's running Windows 95/98 and Windows NT version 4.0. Details...

Q. What is the advantage of using Bishop's method? Back to top of page
A. Bishop's method is suited to most stability problems where a circular failure surface is likely. It is easy to run and always produces a result, since it only considers moment equilibrium.

Q. What is the advantage of using Spencer's method? Back to top of page
A. The Spencer method is suited to both circular and non-circular problems and is theoretically more accurate than Bishop's method. However, in practice, the factors of safety determined by Spencer's method and Bishop's method for circular failure surfaces are almost identical. In some situations it can be difficult to get a result when using Spencer's method since the force and moment equilibrium calculations may not always converge. For these instances, GALENA allows for inclusion of a tension crack of a user-defined depth to be generated automatically.

Q. What is the advantage of using Sarma's method? Back to top of page
A. The Sarma method is suited to more complex problems using non-vertical slices. Slice boundary properties can be set independently of surrounding material properties, thus allowing modelling of discontinuities. It can even be used to simulate foundation problems.

Q. How are non-vertical slice boundaries generated when using Sarma's method? Back to top of page
A. GALENA will normally generate slice boundaries for Sarma's method automatically, and will put a slice boundary in at every point where there is a change in either slope profile or failure surface. These slice boundaries will be drawn approximately at right angles to the failure surface and the failure plane.

However, GALENA also allows slice boundaries to be input at (almost) any orientation and allows the user to specify material properties for that slice boundary. For example, two slice boundaries may be specified manually and then GALENA would also include other slice boundaries automatically. The automatic slice boundaries would be sub- parallel to the two manually specified slice boundaries.

The strength assigned to automatic slice boundaries is calculated as the average value of the material properties for the model. In this way, a fault can be given low material properties by using a manual slice, but the material either side of the fault will have the properties of the model by using automatic slices.

Manual slices are defined using the SLICES command.

The slices command is quite smart and will adjust itself automatically to an exact size to fit between the failure surface and the slope profile. For example, a long slice boundary can be input manually and when previewed (with the preview option) its full length is shown. However, when the model is run the length will be truncated and only the exact length used is shown.

Q. Does GALENA use other methods of analysis, eg. Fellenius, Corps of Engineers, Morgenstern-Price? Back to top of page
A. The design philosophy behind GALENA is to provide engineers with tools to solve problems quickly and efficiently, and the methods of stability analysis provided in GALENA will enable engineers to do this.

We believe it may be both confusing and misleading to have many different methods of analysis all providing different answers to the same problem. In this case, the engineer then has to decide which result is realistic, which can be an unnecessary complication.

For circular analyses most of the methods of stability analysis give similar answers, and the Bishop Simplified Method is widely recognised as producing realistic results.

For non-circular analyses, the Spencer method satisfies both moment and force equilibrium conditions and normally gives a reliable answer. The Morgenstern and Price method is similar to Spencer's method except that it allows for a variable interslice force angle on every slice and is theoretically more 'mathematically' correct. However, the variation in interslice force angle is generally unknown for almost all problems and therefore the result could in fact be less realistic using the Morgenstern and Price method than using Spencer's method. Also, the Morgenstern and Price method can have convergence problems.

For complex problems, the Sarma method is the only method that allows for non-vertical slices, and separate material properties to be specified for slice boundaries. The Sarma method can also be used for foundation or other complex geological problems.

Note that no method is 'correct' and that the stability of a slope is independent of the method of analysis. GALENA gives you the methods of analysis to obtain realistic results.

Q. How can pore pressures be modelled? Back to top of page
A. Pore pressures can be modelled in GALENA in several different ways:
  1. a simple phreatic surface that applies to all material below that phreatic surface;
  2. a piezometric surface that can be applied to one or any number of layers such that there can be a separate pore water pressure regime for each layer (confined aquifer);
  3. pore water pressures can be specified as an ru pressure for each layer;
  4. density values can be assigned to a liquid in the slope and above the slope. For example, a tailings dam may cause the ground beneath it to be saturated with water (with a density of 9.81 kN/m3) but the density of the tailings slurry may be greater than water (say 11 kN/m3). In this case the uplift pressure from the tailings is still that due to water (9.81 kN/m3) but the stability effect is that due to the tailings (11 kN/m3). This feature enables the user to assign a phreatic surface as a horizontal straight line and simply specify 9.81 kN/m3 for a density below the slope, and specify a density of 11 kN/m3 above the slope. We find this to be a very convenient and useful feature.

Q. Can pore pressures be simulated by inputting a grid of pore pressures? Back to top of page
A. Pore water pressure input from a pore pressure grid is not included at present for the following reasons:
  1. A pore pressure grid assumes that the pressure at the base of the slice is equivalent to the pressure due to the equipotential line, and this pressure is slightly less than the pressure due to the vertical distance from the base of the slice to the phreatic surface. However, this loss in head is actually dissipated by causing a 'drag' on the material particles in the direction of the seepage, which is usually in the direction of the failure. Therefore, in practice the 'real' pore water pressure is probably better simulated by using a standing head, than by using an equipotential line. An equipotential line may, in fact, be too optimistic.
  2. GALENA is a complete, stand alone package, and does not require any other seepage packages to be run before being able to run stability analyses.
  3. Many geotechnical, mining and civil engineers need to analyse a large number of options rapidly. This cannot be done practically if a finite element seepage analysis has to be run each time as well.
  4. Rock mass permeability information is not always available or accurate, and a single fault or joint can totally disrupt a seepage analysis model.

Q. Can an increase in strength of clays with depth be simulated? Back to top of page
A. Yes, GALENA allows the user to specify an increase in Cu with depth after Skempton's relationship using plasticity index and overburden pressure. Or, effective parameters can be specified for different layers.

Q. What is the limit to the number of trial failure surfaces used? Back to top of page
A. There is no set limit for an analysis run, however, we would recommend a sequential approach using say 200 trial failure surfaces initially, then reducing the search area and trying a further 100 surfaces, etc...

Q. What is the RESTRAINTS command? Back to top of page
A. GALENA allows the user to specify where to search for a critical failure surface, and this is done with the RESTRAINTS command. The most common way to do this is to specify a restraint zone near the toe of the slope and a restraint zone behind the crest of the slope through which the critical failure surface is likely to pass, as well as a radius range for circular surfaces or mid-point deflection range for non-circular surfaces.

Q. What is the BACK ANALYSIS command? Back to top of page
A. This is a feature of GALENA which enables the user to specify a required factor of safety (not necessarily FOS=1.0), for which GALENA will determine the strength required to achieve that factor of safety for the given slope and material, and graphically display the strength relationship.

Q. How are GALENA data files generated? Back to top of page
A. GALENA has its own built-in smart editor with drop-down menus, dialog and data entry boxes making it very easy to generate a data file, and to edit data files using GALENA's fast-edit function.

Q. Can output files be generated for use with other packages, and in what formats? Back to top of page
A. Yes, GALENA generates graphics and print files for review in GALENA. The print files, and output graphic files created by GALENA in various formats, can be included into reports using most word processing packages. GALENA can create HPGL, Postscript, colour Postscript and GEM graphic files for this purpose.

Q. Does GALENA have a hardware security key? Back to top of page
A. No, not for copies distributed after 1 October 1996. Previously GALENA did have a security key. With the advent of Windows 95 and NT we decided not to use security keys in favour of a simpler software protection system. GALENA can still be provided with a security key on request for those who may wish to regularly move GALENA to notebook PCs, or may prefer security keys. Security is designed to protect your investment.

Q. What detailed information is available when using GALENA? Back to top of page
A. GALENA comes with a detailed Users' Guide, including a simple tutorial, an example of the use of all the GALENA commands, and example data files on disk, that will ensure you can learn GALENA quickly.

Q. What backup and support is available? Back to top of page
A. We provide assistance to ensure GALENA will run for you. We can be contacted by telephone, facsimile and e-mail via the Internet for questions you may have on using GALENA. We can also provide a service to analyse any of your problems - our standard consulting rates would normally apply for this work, but most problems would rarely take more than a few hours.

Q. Has GALENA been independently checked by anyone? Back to top of page
A. Yes, a very early version of GALENA (called SLOPANAL2) was verified in the ACADS report in 1990. SLOPANAL2 came out very well in this report. However, it should be emphasised that significant improvements were made to the original program to produce GALENA and we now believe it is the most user friendly slope stability package on the market. The ACADS files are supplied with GALENA for users to verify the results if they wish, and with the growing number of users there are many more 'checks' being carried out.

Q. Who uses GALENA? Back to top of page
A. GALENA was officially launched in February 1992. It has gained rapid approval and is being used by major mining companies such as Hamersley Iron, Northparkes Gold, Renison Goldfields and PosGold in Australia; BHP Minerals operations in Mt Newman, Queensland, San Francisco and New Mexico; BHP Copper operations in Papua New Guinea and at Escondida in Chile; Iscor, Ashanti Gold, and Anglo American Corporation in Africa; Kaltim Prima Coal, Batubara Bukit Asam and Mumut Copper Mining in Indonesia; Coal Corporation of New Zealand, and more recently by some of the larger mining companies in South America, including operations either managed or owned by companies such as Exxon and Placer Dome.

Major engineering and mining consultants using GALENA include Berdal Stromme, BHP Engineering, CMPS&F, Connel Wagner, Coteprol, Douglas Partners, Franken Consult, GH&D, Golder Associates, Howard Humphreys, Knight Piesold & Partners, Maunsell Geotechnical, Rust PPK, Tonkin & Taylor, US Army Corps of Engineers, Woodward-Clyde, Works Consultancy and Worley Consultants. GALENA was recently selected by the United Nations Development Program for the Mongolian Technical University in Ulaan Baatar for use in training and setting up of a consultancy for that country's growing engineering field.

Regulatory bodies, Government departments and authorities using GALENA include Australian Construction Services, Water Resources and Mines departments in Australia, Hydro-Electric and Electricity authorities in Australia, Canada, Mexico and Nicaragua; Melbourne Water, Queensland Railways, Highway and Main Road departments in Western Australia, Virginia, Missouri and Washington; Indian Bureau of Mines, Central Mining Research Institute and National Institute of Rock Mechanics in India; and Geological Survey divisions in Britain, USA, Papua New Guinea and Australia. GALENA is also used by the Western Australian Mines Department to verify all open pit slopes in that state.

GALENA is being used by an increasing number of Universities and Educational Institutions (35 to date) for teaching and research purposes in Argentina, Australia, Austria, Brazil, Chile, Germany, Greece, Indonesia, Italy, Macedonia, Malaysia, Mexico, New Zealand, Poland, Serbia, Slovenija, South Africa, Sweden, Turkey, UK, USA and Venezuela.

Finally, GALENA has been reviewed by the US Office of Surface Mining and Mine Health and Safety Authority in Pittsburgh and they indicated to us that they prefer GALENA to all other slope stability software they are aware of.

To date there are more than 465 GALENA users, in 50 countries around the world.

Return to GALENA Intro Page.