- GALENA - a powerful and easy to use slope stability analysis system developed for engineers who would rather solve geotechnical problems than computer problems.
- GALENA is engineer-friendly software, designed to be easy to use and to save you time.
- GALENA data structures are logical - definition is available at the press of a button.
- GALENA offers clear graphical images for a clear understanding of the situation being modelled.
- GALENA is a menu-driven program with toolbar buttons for all definition options, which makes it easy for first time users.
- GALENA's model and analysis structure is designed for 'what if' scenarios with single option amendments for additional analyses.
- GALENA's unique features are designed to provide users with the tools needed to take much of the guesswork out of the natural variability of geological materials.
- GALENA is the program of choice of the US Government's Office of Surface Mining.
What's New in Version 6?
- Enhanced Material Colourbars, together with user control for material colour display on model and result images... click here for more information.
- Material Properties extended to allow definition of saturated and non-saturated properties for each material.
- Extended use of material colours (on dialogs), and Figure Number options (for result images).
- Improved Help utility, with more information and detail.
- Improvements to the use of Skempton’s relationship.
- Material Profiles re-ordering option added.
- Material Properties extended to allow angular ranges to be defined for Anisotropic materials, in addition to the elliptical relationship model.
- Improved and automatic Material Keys (legends) on analysis result images, including the material colour, description and properties.
- Position related (interactive) display of Cohesion/Phi for BackAnalysis result images.
- More processing options (Express, To Last Edited).
- Updated and enhanced Analysis Result summary.
- Simpler access to saved Analysis Result Images.
FEATURES IN GALENA
Failure Surface Definition
Have you ever battled with circular failure surface definition using the traditional concept of an abstract point in space? And then tried to relate that surface to the slope surface?
The old way is just that - again, GALENA introduced a better way!
Circular Failure Surface definition using circle centres can be a thing of the past with GALENA's unique approach of definition in terms of the actual slope rather than an abstract point in space.
With GALENA you can define circular failure surfaces simply, by defining their X co-ordinate intersection points with the slope surface (X-Left & X-Right), together with a nominal or desired radius, and leave the hard work to GALENA.
GALENA can of course still use the more traditional definitions; you can even combine the more traditional definitions with those provided by GALENAs innovative and leading approach.
Definition of non-circular failure surfaces is either with GALENA's CAD-style mouse line-draw function, by keyboard co-ordinate entry, or a combination of both - you can even create a non-circular failure surface from a circular failure surface in a few easy steps.
Definition made easy - the way it should be!
The image below shows a simple slope with an embedded material lense (shown in red-brown) with a phreatic surface passing through it - the material lense is simply modelled as a closed polygon.
The circular failure surface is defined by its X-Left and X-Right positions together with a nominal Radius and is now ready for a multiple analysis.
Embedded material lenses are simply defined in GALENA, and we have been advised (a number of times) that GALENA is the only program that can include material lenses thus.
The image below shows a simple horizontally-bedded slope with a thin weak clay layer (shown in yellow) just below the surface of the lower part of the slope. A phreatic surface exists at the base of the weak clay layer.
A non-circular failure surface has been defined (using GALENAs mouse line-draw function to position part of the failure surface within the weak layer.
The model is ready for a multiple analysis - restraints have been defined to ensure the trial failure surfaces generated for analysis are all within the area of interest (within and around the weak clay layer).
Material Strength Criteria
The days are gone when you needed a program to analyse soil slopes and another to analyse rock slopes - GALENA provides you with both the Mohr-Coulomb and Hoek-Brown criteria for definition of material property strengths, so you can effectively and efficiently handle both soil and rock slopes using the one program.
GALENA provides you with the ability to use the Mohr-Coulomb and Hoek-Brown material strength criteria, and shear/normal stress relationships, for assessing stability of both soil and rock slopes.
With such facilities available in GALENA the need for a specialised and separate rock slope analysis package vanishes.
Mohr-Coulomb strength criteria is defined in terms of cohesion and angle of shearing resistance (c/phi), together with a material density. GALENA can also calculate and use increasing cohesion with depth according to Skempton's relationship for cohesive soils.
Hoek-Brown strength criteria can be defined in terms of m, s and UCS, together with a material density. Shear/normal stress data representing linear, curvi-linear, or similar relationships of your choice can easily be entered or imported.
GALENA also includes tables and Tools functions that enable you to estimate material properties for cohesive and non-cohesive soils, according to published data and information.
Tables and Tools functions are also included that enable you to determine RMR (Rock Mass Rating) from input parameters according to Bieniawski. Calculated or entered RMR values can also be used to calculate suggested strengths based on the works of various published authors.
The Mohr-Coulomb and Hoek-Brown criteria, as well as shear/normal data, can be used with all methods of analysis within GALENA, not just the Sarma method of analysis.
Material properties can also be defined for slice interfaces when using the Sarma method of analysis in GALENA, thereby allowing you to model discontinuities and/or joints that may have properties different to those of the surrounding materials. You can of course choose not to define material properties for slice interfaces and simply leave it to GALENA to automatically determine slice interface properties from surrounding materials.
The image below shows the results of an analysis of a proposed earthen retaining structure where the Factor of Safety was found to be unacceptable due to the nature of the existing foundation materials.
Note the distortion of the failure surface that has occured as a result of Restraints applied to an initially-defined circular failure surface - GALENA can generate and analyse non-circular failure surfaces from input circular failure surfaces.
The image below shows the analysis results after Stone Columns were included within the foundation for the same structure - a significant improvement in the Factor of Safety was noted that provided an impetus to the feasibility study for the proposed structure.
Sophisticated Geological Modeling
One of the unique features available only within GALENA is in the area of material profiles and slope surface definition, a feature that recently led one observer (a university professor) to candidly comment to us "I can see why GALENA walks over everything else available to the mining industry." And that was after a brief 15 minute presentation!
GALENA allows you to define geology or slope makeup as it exists or will exist, without first defining the slope surface, thus providing for rapid assessment of design options.
What this means is that the slope surface is entirely independent of the material profiles (that define geology or material layers), and can be moved, modified or re-positioned without changing, moving or re-defining any of the material profiles.
This unique feature also means that you save time by not having to re-define or change your material layers every time you want to change the slope surface, which is the way it should be - Stability analysis shouldn't be an uphill battle!
We should emphasis here that it is not necessary for the user to remove or strip away any of the profiles or materials that lie above the slope surface when modelling in this way, at any time - that is handled entirely and automatically by GALENA.
To better understand this feature have a look at the following on-screen images:
* This image shows the model initially with geology defined first (using profiles); material properties have been defined for each material (colour bands on each profile represent the material associated with that profile); and labels have been added to aid identification.
Then, as shown in the image below, the slope surface is defined (based on the mine plan in this case) - expected or known water conditions are then defined along with an expected failure surface for analysis.
It should be noted that the slope surface is not tied to any of the material profiles.
Once complete the model can be processed. The result is then displayed, as shown in the image below. (Trial roadway loadings were added subsequent to the first analysis.)
Material profiles above the slope surface have been ignored and are not shown, without intervention or any required action from the user.
Restraints and Searching
In the real world engineers are only concerned with stability within certain physical limits.
GALENA introduced the concept of Restraints, to allow you to focus your investigations on realistic failure surfaces that take account of geological structure.
GALENA's Restraints are based on those parameters and values that are used to define a failure surface so that you have total control over the extent of the search area.
As an example: You are considering a slope where you have concluded a circular failure surface to be most appropriate; Restraints allows you to limit all trial failure surfaces to daylight at the toe of the slope, which we will take to be the X-Left position for the failure surface; Restraints also allows you to define a range for the other end of the failure surface, which will be the failure surface X-Right position, and a range for the failure surface Radius.
All failure surfaces then generated by GALENA will be within the ranges defined for the X-Right position and the Radius, and all failure surfaces generated will have the same X-Left position.
Restraints can of course be used to provide search limits to any of the parameters used to describe circular failure surfaces, including the more traditional abstract points in space used to define a circle centre. Restraints can also be used in a similar way to provide search limits for non-circular failure surfaces, and truly provide you with control over search areas.
As well as providing search ranges Restraints allows you to define the number of trial surfaces to be generated and analysed within each of those ranges. The actual number of trial surfaces is up to you; GALENA can generate and analyse up to around 1 billion trial surfaces for each analysis, although it would be rare to even attempt such numbers.
The norm would be to follow a sequential 'fine-tuning' approach with around 3,000 - 5,000 trial surfaces for an analysis, followed by further analyses using the critical failure surface as a seed.
So, as you can see, Restraints provides you with a very powerful mechanism, that gives you real control in the real world.
The image below shows a model with an evenly distributed load adjacent to the slope toe and an unevenely distributed load behind the slope crest - critical to the stability of the slope is the thin weak clayey layer within the slope, and the perched water table (piezometric surface) therein.
Restraints in GALENA allow the user to define the horizontal search range for both the left and right positions of the failure surface, and for the vertical search range within the weak layer.
Restraints also allow the user to fix the left position of the failure surface (as is most likely in this case due to the adjacent loading), and to concentrate the search for a failure surface with the lowest Factor of Safety in the area around the upper unevenly distributed load.
Another of the unique features available only within GALENA is BackAnalysis, a feature recently commented on by some of our users: "...that marvellous BackAnalysis feature...", "...this BackAnalysis is magic...", "...BackAnalysis really gives us a full appreciation of the situations we are modelling...", "...BackAnalysis is going to save us so much time..." and "...thank you for making BackAnalysis better and easier...".
GALENA's rapid BackAnalysis function takes the trial and error out of determining ground support requirements. It can be used for both back analysis of past failures and for the design of existing slopes. It answers the question of 'What strength is required?', rather than 'What is the stability of the slope?'.
BackAnalyses can be undertaken on any model using any of the methods of analysis available in GALENA - you can specify a single or multiple BackAnalysis. For a single BackAnalysis you define one Factor of Safety; for a multiple BackAnalysis you define up to ten different Factors of Safety - a curve will be calculated and displayed for each Factor of Safety defined, it's that easy!
BackAnalysis can also be used for Sensitivity Analysis, to help answer the additional questions of 'How sensitive is this slope? and How critical are the material properties we have used?'
With GALENA's rapid BackAnalysis function you can see at a glance the likely range of material properties over a given Factor of Safety range.
The image below shows the results of a Multiple BackAnalysis - each curve is individually labelled with its relevant Factor of Safety.
Water Definition, Pressures and Positions
Ground water pressures, the most important parameter affecting the stability of structures and excavations, need to be defined realistically for different problems. GALENA provides you with the tools to realistically define ground water, and to define water and denser mediums above ground, a feature that GALENA pioneered for tailings dam work.
For realistic water pressure definition for different problems GALENA enables water pressure to be defined as:
* a simple phreatic surface
* a piezometric pressure within one, two..., or all material layers
* an Ru pressure within one, two..., or all material layers
* a dense above-ground liquid medium such as tailings slurry, or water, or
* any combination of these.
GALENA allows definition of a phreatic surface that extends above the slope surface, with a density specified for the resultant above-ground medium - this is particularly useful for modelling water retaining structures such as dams, tailings dams or slurry pondages.
Phreatic surface definition is simple - just two points in many cases, and GALENA's CAD-like mouse-draw functions make for easy definition of draw-down and non-planar surfaces.
Phreatic surface definition in GALENA also provides a simple way of modelling a fully or partially saturated slope where the density of the medium-above-ground is simply defined as 0.0 (zero).
These and other features are simply part of the way GALENA makes it easier for you.
The image below shows a complex dam with a clay core. The bedrock layer (sandstone) contains a piezometric surface (shown in cyan and labelled); and the dam water level (shown in blue and labelled) is modeled as a phreatic surface. The phreatic surface defines the water level behind the dam and within the dam structure, and controls the pore-water pressures within the weathered sandstone and clay layers.
It should be noted that with GALENA both the upstream face and downstream face of the dam can be analysed using the one model, simply by defining the failure surface appropriately - there is no need to flip the model over to analyse the two faces.
Material Profile Definition
Have you ever been frustrated with having to move or redefine material profiles whenever you want to change the slope surface? Or wondered why you cannot realistically model complex geology? Or how to include material lenses?
Great News! The old ways are no more - GALENA introduced a better way!
With GALENA's unique approach the material profiles are independent of the slope surface - changing the slope surface does not require material profiles to be changed.
To take advantage of this feature all you need do is define the material profiles first and according to geology. Its that simple!
For example: You have a simple layered geology and you want to design a slope within that structure. With GALENA you define the layered geology as simple horizontal/dipping profiles and create a model that resembles the geology/structure. You then define a slope surface to model the slope you wish to have, define a failure surface and analyse the defined slope. If the Factor of Safety is too low (or too high) and you want to redesign the slope you simply redefine the slope surface and analyse the new slope - none of the material profiles need to be moved or redefined.
The old and more conventional method involves moving all or most of the material profiles and making sure they follow the slope surface - not necessary with GALENA. You can, however, still use the old method, if you have the time!
Another of GALENA's unique features is the ability to model included material lenses - simply draw them into your model as closed polygons, and GALENA will do the rest.
GALENA can also be used to model complex situations including vertical or near-vertical folding, included structures (retaining walls, sheet pile walls, etc.), dams and cofferdams.
Definition of Material Profiles, Slope Surface, Phreatic Surface, Piezometric Surfaces, Non-Circular Failure Surface and Sarma Slices can either be with GALENA's CAD-style mouse line-draw function, by keyboard co-ordinate entry, or a combination of both.
Definition made easy - the way it should be!
The image below shows a proposed tailings dam staged-augmentation project - the profiles with the yellow colour band represent the tailings, and the profiles with the grey colour band represent the core material. Most of the profiles used in the augmentation study are defined by two or three points.
Should it prove necessary to steepen the slope surface it would be a simple matter of re-defining or editing the slope surface, only. To widen the stage core would only require two points on seven profiles to be shifted to the right, much less work than a complete re-definition of the model, including all profiles, as in most other programs.
Defining Forces and Loads
To correctly model many slope stability problems it can be necessary to include earthquake forces and external loads or forces that may have a direct bearing on the stabilty, or instability, of the slope under examination.
GALENA provides you with the functions necessary to model most situations using:
- Earthquake forces
- Externally-applied distributed loads
- Externally-applied point forces
Earthquake forces can be applied to models as a seismic coefficient, and can even be used to model blast effects.
Distributed loads can be evenly distributed, or unevenly distributed - GALENA provides functions for for both, so that you are able to correctly and easily define simple and complex loads, including vehicular, roadway/railway, structural, equipment or dragline/shovel loadings.
Point forces of any value can be applied at any position and at any angle on the slope surface.
Tension cracks can be used within GALENA, and can be either manually defined, or can be of a specified depth for GALENA to automatically generate on-the-run for inclusion in all analyses - a particularly useful feature for multiple analyses.
The image below shows the use of an unevenly distributed load (nearest the slope crest) in conjuction with an evenly distributed load (immediately to the right of the first load). Quite complicated loading scenarios are possible with the Distributed Load feature in GALENA. This model also includes an earthquake force, indicated by the red arrow and value above.