Numerical modeling software for advanced engineering analysis of jointed and blocky material, groundwater, and structural support in three dimensions.

www.itascacg.com/3dec

3DEC 5.2 3DEC is a three-dimensional numerical modeling code for advanced geotechnical analysis of stability, ground water flow, and ground support of discontinuous materials (such as soils, jointed rock, or masonry blocks) undergoing loading.

Materials are represented as an assemblage of discrete blocks based on the Distinct Element Method (DEM). Discontinuities are treated as boundary conditions between blocks along which large displacements and rotations of blocks may occur. Individual blocks may behave either rigidly or as deformable, meshed zones.

Continuous and discontinuous discontinuities may be generated:

• deterministically by specifying orientation, length, gap, and spacing;• statistically by including standard deviations values;• using FISH to script custom parameters and distributions;• using sets of Discrete Fracture Networks (DFN) of 3D disks, which can be

generated statistically or imported from geologic mapping data or third-party software such as Fracman.

FISH scripting also allows users to write their own scripts to add functionality for custom analyses. UDEC is the two-dimensional equivalent of 3DEC.

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Cover images, top left and going clockwise:

• Pillars in jointed rock with rockbolts supporting the span in between. The yellow material is ground between the pillars that has mobilized.

• Cut-away view of a geological model defined by nine intersecting faults.• Large open-pit mine intersected by three major faults showing slope movement on the

west wall.• A scale model of the 15th century Mustafa Pasha Mosque in Skopje, which underwent

a comprehensive shake table program, is modeled by the discrete element approach. Figure courtesy of Özden Saygili (http://dx.doi.org/10.1016/j.engstruct.2016.07.044).

LICENSES 3DEC licenses (and any enabled options) have two parts: the “license term” and the “license type”. The license term may extend over a period of time of a monthly lease, an annual lease, or in-perpetuity. The license type may be either a standard or network USB security key (i.e., hardware lock). When the USB key is not present, the program operates in Demonstration Mode.

STANDARD LICENSEA stand-alone, single-user program. The standard type will allow two instances of 3DEC to cycle simultaneously on a single computer. There is no limit to the number of instances that may be open without cycling. This allows an unrestricted amount of model setup or analysis. The program is secured with a USB key that must be connected to a computer to allow cycling. The USB security key may be moved between computers and users as needed. This option is ideal for an individual or for multiple users utilizing the software within the same office.

NETWORK LICENSEThe software will cycle a number of 3DEC instances equal to the number of seats purchased for the license. The USB security key and license management software are installed on a server while the 3DEC program is installed on end-user computers. The program may be installed on as many computers as needed. This license is ideal for a centralized, IT-administered organization.

DEMONSTRATION LICENSEWhen no key is present, a dialog provides the option to start the program in Demonstration Mode. This mode is fully functional in every respect, except the program will only cycle models limited to 40 blocks and 1000 zones. There are no time restrictions in Demonstration Mode.

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APPLICATIONSUse 3DEC for stability, remediation, and other geotechnical and groundwater analyses in civil, environmental, mining, oil & gas, and power generation engineering fields. The following examples are highlighted, but through scripting and custom constitutive models, the possibilities are virtually limitless.

CIVIL• Slopes• Tunneling• Shafts• Caverns• Excavations• Foundations• Masonry architecture and structures• Earth retaining structures• Embankments• Rockfill and concrete dams• Harbor structures• Dewatering and water flow• Pavement and subgrade• Waste disposal

MINING• Open-pit slopes and benches• Dewatering and water flow• Tailings dams• Underground stopes, shafts,

tunnels, caverns, and passes• Room and pillar mining• Waste rock piles• Blasting and rock bursts• Ground subsidence• Backfill design• Solution mining• Longwall mining

OIL & GAS• Conventional and unconventional• Well completions• Enhanced recovery• Fluid injection• Hydraulic fracturing• Wellbore optimization• Casings• Borehole breakout• Sanding• Fault movement and integrity• Compaction and subsidence• Salt caverns• Reservoir-scale modeling• Cap rock integrity• Microseismics• Proppant behavior

POWER GENERATION• Engineered geothermal systems• Hydroelectirc dams• Nuclear waste isolation• Hydro/thermal plants• Hydroelectric power houses• CO2 sequestration• Wind turbine foundations• Engineered barriers• Cap rock integrity

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3DEC model of a tunnel intersected by three joints forming a wedge (orange). New cable bolt tools and enhanced visualizations of bolt performance are available to analyze tunnel performance.

Displacement contours indicating the movement of jointed rock, with major intersecting faults, in the crown of a large power house surge chamber.

3DEC hydraulic fracturing model showing high pore pressure contours near the injection point and fluid flowing outward along the joints defined by a Discrete Fracture Network (DFN).

FEATURES3DEC is ideally suited to analyze potential modes of failure directly related to the presence of discontinuous features. Work with either discrete blocks, zoned continuum, or both. It includes 13 built-in zone material models, three built-in joint models, groundwater flow (matrix and joints), coupled mechanical-flow calculations, ground support structural elements, and

a built-in scripting language (FISH) that can customize or automate virtually all aspects of 3DEC operation, including user-defined properties and other variables. 3DEC can be extended with four options (Dynamic, Thermal, Surface Liner, and C++ User-Defined Constitutive Models) that are offered separately from the base program.

GENERAL• Built-in project management tools, text editor, automatic movie-frame

generation, and extensive plotting capabilities. • Ideal for modeling large movements and deformations.• Accurate simulation of fast rotating rigid blocks.• Blocks may be rigid or automatically zoned to make deformable blocks.• Optimized to solve problems requiring non-linear multi-physics.• 64-bit, double-precision calculations.• Multi-threaded algorithms with no CPU locks or additional CPU fees.• Includes groundwater joint fluid-flow.• Includes groundwater matrix (i.e., permeable solids) fluid flow. NEW

• Fluid flow may be either uncoupled or fully coupled hydromechanical.• Built-in scripting language, FISH, provides powerful user-control to

parameterize, analyze, review, and modify nearly every aspect of the simulation, even during cycling.

• Track histories of model properties and results throughout the model to allow for comparison to actual monitoring and instrumentation data.

MODEL CONSTRUCTION• Block generation using primitives (face, tetrahedral, brick, drum, and prism). • Automatic tunnel region generator from tunnel profile.• Automatic mesh generation in fully deformable blocks using tetrahedral and

hexahedral zones (including mixed-discretization).• Zones can be converted into bonded block models. NEW

• Easily separate objects into separate geometric regions using geometric surfaces, volumes, or geometry offsets.

• Geometry creation using polygons.• Results visualization (property/results painting) on DXF or STL geometry.

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• Create regions using cubic blocks cut by user-defined outlines.• Wall-type blocks speed up model runs as motion and wall-to-wall contacts are

skipped in solution cycles.• Built-in block zone densification for hexahedral and tetrahedral (NEW) mesh

refinement, including automatic octree generation from surfaces and volumes.• Built-in ability to assign groups based on counting projection intersections for

defining complex groups and ranges for blocks, zones, gridpoints, contacts, and subcontacts.

MATERIALS and CONSTITUTIVE MODELS• Includes null, three standard elastic, and nine plastic constitutive models:

• Null (for construction sequence and excavation)• Elastic (isotropic, transversely isotropic, and orthotropic)• Drucker-Prager• Mohr-Coulomb• Ubiquitous-joint (UBJ)• Strain hardening/softening• Bilinear strain hardening/softening UBJ• Double yield• Modified Cam-clay• Hoek-Brown• Modified Hoek-Brown

• Includes three built-in joint material models:• Elastic• Mohr-Coulomb• Continuously Yielding

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New bonded block model (BBM) tools have been added to 3DEC so that bonded tetrahedra elements can be used to simulate a massive rock. The bonded blocks may then break apart due to stresses.

• Specify statistical distributions for material properties.• Groundwater fluid flow analysis is included, with:

• Water table (effective stress)• Steady-state• Transient

• Proppant simulation in fluid-filled joints. NEW • Create, load, and run customized zone and joint models via C++ (option).• Includes creep material models to simulate time-dependent material behavior.

JOINT SETS and DISCRETE FRACTURE NETWORKS• Joint structures can be built into the model directly from geologic mapping.• Specify continuous and discontinuous joint sets by orientation, number or

spacing, origin, and persistence.• Random seed values and statistical deviations can be utilized to create

multiple realizations (examine sensitivities and risk).• Easily define non-persistent joints and their properties.• Incorporate Discrete Fracture Networks (DFNs) by specifying density and

orientation-, size-, and position-distributions for circular disks or polygons.• Import both Itasca circular disk or Fracman polygon DFN data formats.

BOUNDARIES and CONDITIONS• Discontinuities (interfaces, joints, joint sets, and DFNs) are regarded as distinct

boundary interactions between blocks; joint behavior is prescribed for these interactions.

• Stress, applied force (load), and velocity boundaries can be defined.• Structural elements for ground support include: beams, cables, and

(optionally) liners.• Add external infrastructure (such as dams, bridges, walls, buildings, etc.) as

finite element structures (optional).• Time-varying boundary conditions can be defined.• Couple detailed and larger far-field models for better solution efficiency.• Define in-situ stresses and stress gradients.• Includes tools to easily transfer field stresses to model stresses.• Automatically assign in-situ stresses based on model surface topology, depth,

material density, and stress-ratio values. (NEW)• Quiet (i.e., non-reflecting) and free-field boundaries (with dynamic option).

FISH SCRIPTING• Provides powerful functionality to parameterize, analyze, review, and modify

nearly every aspect of the simulation, even during cycling.• Built-in text editor provides command syntax error checking and context

sensitive help for simpler, faster model generation.• Inline FISH (add FISH scripting within a command).

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• Export ASCII/binary data files; exchange information with third-party software.• Assign/read extra variables for nearly all model parts (blocks, contacts, etc.).• Filter blocks, zones, gridpoints, and contacts by groups and slots (layers).• Full scripting access to geometric data.

FACTOR OF SAFETY ANALYSIS• Automatic, fast solutions using the shear strength reduction (SSR) method and

a converging bracket approach.• Applicable for Mohr-Coulomb, Ubiquitous-Joints, Hoek-Brown, and Modified

Hoek-Brown constitutive models.• Color blocks by excess shear stress or factor of safety for a given hypothetical

set of joints. NEW

POST PROCESSING• Extensive visual plotting capabilities, including contouring on blocks, zones,

and joint surfaces; scalar, tensor, and vector plots; 3D isosurface contouring of gridpoint and zone data.

• Equal area and equal angle stereonet plotting of DFN joint orientations, joint normal orientations, and orientations of major, minor, and intermediate principal stresses.

• Automatically export a series of plot images at regular cycle intervals to create a video-ready image set (third-party software required for video assembly)

• Easily export history results to spreadsheet-compatible CSV files.• Export plots as PNG, DXF, VRML, SVG, and PostScript formats or as a data file.• Track and plot fragments (i.e., disconnected groups of blocks). NEW

Automatic factor of safety analysis for a jointed slope indicates that it is stable with minor movements of some blocks.

WHY CHOOSE 3DEC?POWERFUL• Both continuum and discrete model

simulations possible• Numerical stability with large

displacements, including collapse• Build very large models (64-bit)• 13 built-in material behaviors• Automatic factor of safety analysis• Capable of groundwater flow,

thermal, and dynamic analyses • Coupled solutions• Accommodate complex materials

and pore pressure distributions• Assess service limit state criteria• Create custom functions using FISH• Load and run custom User-Defined

material Models via C++ (optional)

EFFICIENT• Multi-core processing• Optimized solution calculations• Customize material behaviors

efficiently using optional C++ User-Defined Models (UDM)

RELIABLE • Realistic physical solutions• Natural evolution of failure• Transparent methodology with

all equations and algorithms fully documented

• Built-in constitutive models are open-source; no black boxes

• Strong software support led by an experienced team of engineers, scientists, and software developers

• Extensive manuals and documentation

• Automated update notification

PROVEN• Tested against analytical solutions• Used by Itasca’s own consulting

engineers and scientists• A large repository of worked

examples and validations with more than 1,400 published journal and conference papers and theses

• Used worldwide by a wide variety of industries, universities, and government agencies

FLEXIBLE• General by design• Access to almost all internal

variables using FISH scripting• CAD interoperability• Import/export data using ASCII• Human-readable data files• Users may write their own

constitutive models and may modify or add to most of the built-in algorithms using the optional C++ UDM

• Standard license is portable between computers and users

• Multiple seat network licenses available

• Monthly and annual leases available

ECONOMICAL• No CPU limits• No annual maintenance fee• Academic discount• Two instances of 3DEC can be run on

a single computer with a standard license

• Standard license is portable between computers and users

• Monthly and annual leases available

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NEW in 3DEC 5.2 The latest 3DEC software offers about 2x faster run time performance and even greater improvements to model set-up time. A powerful set of new features provides major enhancements, particularly for bonded block modeling and hydraulic fracturing.

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ENHANCED PERFORMANCE3DEC model solutions (contact calculations and fluid flow analysis)have been sped-up through algorithmic improvements, including more powerful cell space and contact detection logic, and multi-threaded calculations. This enables 3DEC to utilize multi-core CPUs to cycle up to 2x faster for typical applications.

Adding joint sets and cutting unjoining, deleting, and excavating (nulling) blocks, making blocks deformable, and the application of external boundary conditions operations have been significantly improved making model set-up much faster.

Zoning algorithms have been improved for better quality zone generation and automatic detection of any negative zone volumes. Rigid block analysis is also more numerically stable.

STRUCTURAL ELEMENTSThe following enhancements have been added to cable structural elements:

• cable elements in 3DEC may now be used in dynamic simulations• forces can now be applied to cable nodes• FISH scripting intrinsics have been added to access cable node,

element, and property data • a grout friction coefficient has been added so grout strength can

be a function of confining stress • new FACEPLATE keyword connects the first node of the cable to

the grid• improved plotting of cable performance and querying of cable

state and properties

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PROPPANT SIMULATIONThe transport and placement of proppant within fractures is modeled by representing the proppant and fracturing fluid as a mixture (assuming the proppant particles are small compared to the fracture opening, and the proppant in the mixture is given by its volumetric concentration).

The proppant logic takes into account fluid-mechanical coupling and several effects are represented, such as:

• pack-formation (when the concentration reaches a given value, the proppant forms a pack, leaving only the fracturing fluid to flow through);

• bridging (when the proppant stops if the fracture width is small enough, compared to the particle size);

• proppant convection (when density gradients cause fluid motion in the fluid loaded with proppant);

• settling (when there is a slip in velocity between slurry and proppant, caused by gravity); and

• viscosity changes as a function of proppant concentration.

FLUID FLOW in JOINTS and ROCKIn addition to simulating fluid flow through joints, 3DEC can now simulate fluid flow between joints into the surrounding material (i.e., leak-off) representing a saturated, permeable solid, such as soil or fractured rock mass (i.e., matrix).

As with joint flow, matrix flow modeling may be either coupled or uncoupled to the usual 3DEC mechanical calculations.

BONDED BLOCK MODELINGNew tools have been added to 3DEC so that it can be used to simulate a massive rock as bonded polyhedral elements (e.g., tetrahedra) that can break at their subcontacts as a result of stress concentrations.

This permits realistic simulations of the initiation and propagation of cracks leading to extension and shear fracturing (i.e., damage), as well as the rock mass strength dependency on confinement, and mechanisms such as spalling and bulking.

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k = 10-8 m/s k = 10-6 m/s

3DEC’s fracture fluid flow has been enhanced with solid matrix fluid flow (between joints). Pore pressure contours along several major joints and within the intact rock are shown for less (left) and more (right) permeable materials.

3DEC model showing just the rock blocks along the periphery of a tunnel in a jointed rock mass. 3DEC fractures can be added as joints and Discrete Fracture Networks. allowing for statistical variations.

OPTIONSOptions in 3DEC are sold separately from the code license, allowing users to augment the program’s functionality according to their analysis needs. Modules available as options for 3DEC include: Dynamic, Thermal, and User-Defined C++ Constitutive Models.

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DYNAMIC OPTION3DEC simulates the nonlinear response of a system (soil, rock, and structures) to excitation from an external (e.g., seismic) source or internal (e.g., vibration or blasting) sources. It can reproduce the evolution of permanent movements due to yield. Capabilities include specification of velocity or stress-wave input, quiet (i.e., viscous) boundaries, free-field conditions (ideal for earthquake simulation), and damping. The dynamic input can be applied as either a prescribed velocity history or as a stress history.

THERMAL OPTIONThe thermal option in 3DEC allows the simulation of transient heat conduction. There are two separate formulations of the thermal logic. The first is a numerical formulation using the explicit or implicit finite difference method. This method is more accurate for short times and includes thermal-mechanical fluid coupling. The second is an analytical formulation that uses superposition of point heat sources in an infinite medium. This method is suitable for long thermal times and is very fast.

C++ USER-DEFINED CONSTITUTIVE MODEL OPTIONUser-defined constitutive models can be written in C++ for both zoned block materials and joint materials. These are compiled as DLL files that can be loaded and run whenever needed with this option. Itasca maintains an online library of UDM C++ models where users can submit and download novel and useful constitutive models.

FINITE ELEMENT STRUCTURAL ELEMENTSThis option adds the ability to model tunnel liners and external structures (such as dams, bridges, walls, buildings, etc.). The tunnel liner logic automatically places equally spaced triangular-shaped plates on the inside surface of an excavation or tunnel. External structures can be modeled using finite elements that are attached to the 3DEC model.

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Dynamic model showing a pulse emanating along a tunnel and traveling though the surrounding rock across two faults as a velocity contour. Quiet boundaries around the sides and base of the model absorb the incoming waves. The top of the model remains a free surface.

3DEC model showing temperature contours and exaggerated mechanical displacement due to thermal effects along an underground drift above a nuclear waste repository.

3DEC VERSION 5.2

ICG

16-B

RO-3

DEC

-520-0

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www.itascacg.com/3dec

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111 Third Ave. SouthMinneapolis, MN 55401 USATel. +1 (612) 371-4711Fax +1 (612) 371-4717Email software@itascacg.com

3DEC model of an arch dam showing the water level and contours of pore pressure along the joints of the surrounding rock mass. A built-in stereonet chart shows the joint set orientations.