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Frequently Asked Questions
The following are some of the most commonly-asked questions put to us over the years, along with answers that may provide you with a greater understanding of GALENA, and why it has become so useful to the many users around the world.
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What is GALENA?
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GALENA is a powerful, comprehensive and user-friendly Slope Stability Analysis system developed by practising engineers for engineers. GALENA was originally developed for mining applications, and has also been widely accepted as a valuable tool for use in civil and the broader geotechnical engineering fileds, and within teaching and research fields.
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What will GALENA run on?
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GALENA is a 32-bit Windows-based program that will run on IBM and IBM compatible PC's running Windows 95/98/Me or Windows NT4/2000/XP/Vista.
Click here for Details
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What is the advantage of using Bishop's method?
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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.
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What is the advantage of using Spencer's method?
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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 an automatically generated tension crack of a user-defined depth in each and every analysis.
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What is the advantage of using Sarma's method?
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The Sarma method is generally suited to more complex problems using non-vertical slice boundaries. Slice boundary properties can be set independently of surrounding material properties, thus allowing modelling of discontinuities and faults. It can even be used to simulate foundation problems.
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How are non-vertical slices generated when using Sarma's method?
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GALENA will normally generate slice boundaries for Sarma analyses automatically, and will put a slice boundary at every point where there is a change in either the slope surface or the failure surface. These slice boundaries will be approximately at right angles to the failure surface and the failure plane.
GALENA also allows one or more slice boundaries to be user-defined at (almost) any orientation, and allows you to specify material properties for each user-defined slice boundary. For example, two slice boundaries may be user-defined - GALENA automatically includes other slice boundaries, as necessary. The automatic slice boundaries would be sub-parallel to the two user-defined slice boundaries.
The strength assigned to automatic slice boundaries is calculated from the materials the slice boundary passes through. In this way, a fault can be given lower material properties by using a user-defined slice, and the automatically generated slice boundaries either side of the fault would have material properties taken from appropriate model materials.
User-defined slice boundaries are positioned either by specifying end-point co-ordinates, or by drawing them with the mouse.
GALENA's user-defined slice boundary capability is intelligence-based - boundaries can be positioned or defined to go beyond the slope surface or below the failure surface. At run time GALENA automatically adjusts the boundary length to fit between the failure surface and slope surface.
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Does GALENA use other methods of analysis, eg. Fellenius, Corps of Engineers, Morgenstern-Price?
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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 enables engineers to do this.
We believe it may be both confusing and misleading to have many different methods of analysis all providing slightly different answers to the same problem. In this case, the engineer then has to decide which result is realistic, which can prove to 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 generally gives a reliable answer. The Morgenstern-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-Price method than using Spencer's method. Also, the Morgenstern-Price method can have convergence problems.
For complex problems, the Sarma method is the only method that allows for non-vertical slices, and for 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.
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How can pore pressures be modelled?
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Pore pressures can be modelled in GALENA in several different ways:
- A simple phreatic surface that applies to all material below the surface;
- 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 (e.g. a confined aquifer);
- Pore water pressures can be specified as an Ru pressure for each layer;
- 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; or 62.4 lbf/ft3;) but the density of the tailings slurry may be greater than water (say 11 kN/m3; or 70.0 lbf/ft3;).
In this case the uplift pressure from the tailings is still that due to water (9.81 kN/m3; or 62.4 lbf/ft3;) but the stability effect is that due to the tailings density (11 kN/m3; or 70.0 lbf/ft3;).
This feature enables the user to assign a phreatic surface as a horizontal straight line and simply specify 9.81 kN/m3; or 62.4 lbf/ft3; for a density below the slope, and specify a density of 11 kN/m3; or 70.0 lbf/ft3; above the slope.
This has proven to be a very convenient and useful feature for many users in the examination or design of tailings dams and pondage.
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Can pore pressures be simulated by input of a grid of pore pressures?
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Pore water pressure input from a pore pressure grid is not included at present for the following reasons:
- 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.
- GALENA is a complete, standalone package, and does not require any other seepage packages to be run before being able to run stability analyses.
- 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.
- Rock mass permeability information is not always available or accurate, and a single fault or joint can totally disrupt a seepage analysis model.
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Can an increase in the strength of clays with depth be simulated?
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Yes, GALENA allows the user to specify an increase in Cu with depth after Skempton's relationship using plasticity index and overburden pressure. Alternatively, effective parameters can be specified for different layers.
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Is there a limit to the number of trial failure surfaces that can be analysed?
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Effectively, no. Any number (up to around 1 billion) can theoretically be analysed within a single multiple analysis, but realistically most analyses would rarely require more than a few thousand trial surfaces to be analysed.
For most situations we recommend a sequential approach of analysing say 1000-2000 trial failure surfaces initially, then reducing the search area and evaluating a further 300-500 surfaces around the critical surface (from the initial analysis), etc...
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What are Restraints?
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Restraints allow the user to specify and control where GALENA is to search for a critical failure surface.
The most common approach is to specify a Restraint zone near the toe of the slope and a further 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 a mid-point deflection range for non-circular surfaces.
All program-generated failure surfaces will be within the Restraint zones, thus allowing you to concentrate your search to your area of interest.
See the Restraints page for more information...
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What is BackAnalysis?
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BackAnalysis is a unique feature of GALENA that enables the user to specify a required Factor of Safety (not necessarily = 1.0) for GALENA to determine strengths required to achieve that Factor of Safety, for a given material within the slope.
GALENA graphically displays the strength relationship for a single Factor of Safety, or, for Multiple BackAnalyses, a number of required Factors of Safety.
See the BackAnalysis page for more information...
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How are GALENA models created?
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Models are created on screen, with the aid of dialogs for data entry, or with a CAD-like mouse-draw facility for surfaces, profiles and slices, or a combination of both dialog data entry and mouse-draw. The model is updated on-screen at each stage as definition proceeds.
Models can also be traced from a background image, that can be either imported or pasted into GALENA from mine-planning programs and the like, or from scanned images.
Data files from previous versions of GALENA are automatically converted and saved.
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Does GALENA have a security key?
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Simple hardware security keys were used with early (v1/v2) releases of GALENA until October 1996, after which a software security key system was utilised to provide compatibility with Windows 95.
In mid-2000 we re-introduced hardware security keys (for v3), and users now have the choice of a security key for either USB port or parallel port connection.
Hardware security keys are also provided for Network Licence versions of GALENA, for either USB port or parallel port connection, for any number of network users.
The security key chosen by Clover Technology is claimed by the manufacturer to be 'the smallest in the world'. The USB key was introduced with the v3.1 release and can readily be attached to a key-ring, or have a key-ring style identification or ownership tag attached.
Please remember, security is designed to protect your investment, as well as ours.
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Can GALENA be used on a network?
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GALENA is available in two basic Licence options: a Standalone Licence provides for use on a single PC; and a Network Licence provides for use on a number of PC workstations with access to a network server.
The Network Licence option allows GALENA to be installed to a network server and then to be used on any workstation PC with access to the network server - we provide programs to install and remove Shortcuts, and to setup workstations for GALENA use. System requirements...
Model files can be stored either locally on the workstation PC or on any network location. Printed output can be directed to hardcopy devices locally or remotely available across the network.
GALENA can be supplied to allow use by any number of concurrent users, whether it be one or fifty. The number of concurrent users is monitored by GALENA and warnings provided when the Licence maximum has been reached.
Additional users can be added, usually by email or phone, thus avoiding delays to projects or committments.
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What detailed information is available when using GALENA?
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GALENA comes with a detailed on-line Help facility for all dialogs displayed with GALENA, as well as an on-line Users' Guide (in electronic form), which can also be printed.
The Users' Guide includes a simple tutorial to demonstrate basic GALENA operation and definition options, and additional useful information on stability analysis.
The Help facility also includes a number of worked examples, as well as detailed descriptions of all example and verification model files that are provided with GALENA - information designed to ensure you can learn GALENA quickly.
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What backup and support is available?
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We provide assistance to ensure GALENA will run for you. We can be contacted by telephone, facsimile and e-mail for questions you may have on using GALENA, and can assist you when your model definition does not seem to be ‘going right'.
Contact Clover Technology for GALENA support...
If requested we can generally arrange or recommend a consultant to assist you or get you started with analysis of your difficult problems - standard consulting rates would generally apply, but most problems would rarely take more than a few hours.
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Has GALENA been independently checked by anyone?
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Yes, an early version of GALENA (called SLOPANAL2) participated and was verified in the ACADS report in 1990. SLOPANAL2 came out very well in this report.
(ACADS is an Association of Technical Computer User Organisations - ACADS Publication No. U255. The study was undertaken by Monash University, Dept. of Civil Engineering, Melbourne, Australia.)
Significant changes, improvements and advancements have been made to GALENA over the years, to produce what we believe is the most user-friendly slope stability package on the market today. The ACADS files and referee results are supplied with GALENA for users to verify the results if they wish, and with the ever-growing number of Licensees there are obviously many more 'checks' being carried out around the world by competent and knowledgeable GALENA users.
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What is the history of GALENA?
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GALENA was originally developed by BHP Engineering, what was the engineering consultancy division of Australia’s Broken Hill Proprietary (BHP). BHP is now known as BHP Billiton - the world's largest mining and resources company.
GALENA was officially launched by BHP Engineering in February 1992 and gained rapid approval in the mining and civil areas around the world.
Clover Technology assumed responsibility for sales and support of GALENA in February 1998 and ownership in November 1999, and has since developed and released the first Windows version of GALENA (v3.0 in December 1999), followed by v3.1 in August 2001, v4.0 in November 2003, v4.01 in July 2004, and v4.02 in June 2005
The current and most recent release (v5.0) was released in December 2006, updated with v5.01 in September 2007, and again with v5.02 in November 2008 to include even more features and improvements.
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Copyright © 1990-2009 Clover Associates Pty Ltd
Updated: 23 May 2009
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