Soft SpotSoft Spot
Itasca’s Software Newsletter
VOLUME 7 number 1
February 1999
In the Spotlight
3DEC was developed in 1988 as the three-dimensional
extension of Peter Cundall’s distinct element method.
Initially, the program was used as a research tool to sim-
ulate the progressive, large-scale movements of blocky
rock systems. The first applications were in stability
analyses of rock slopes and
underground excavations. Over
the past ten years, the applica-
tion of 3DEC has expanded to
several other engineering fields,
such as stability assessment of
arch dams on rock foundations,
design of underground power
houses, evaluation of the ulti-
mate capacity of masonry struc-
tures, and seismic studies of
historical columns and arches.
3DEC is now an accepted analy-
sis tool for applications involv-
ing jointed or blocky materials.
This issue of SoftSpot focuses on the recent
advancements and applications of 3DEC. The adjacent
article describes what is new with the December 1998
release of 3DEC Version 2.0. We have asked some of
our 3DEC users to provide examples of recent studies
they have performed. These are presented on page 2; a
list of recent 3DEC-related publications is provided on
page 7. I think you will find that 3DEC offers unique
capabilities in modeling large, complex discontinuous
systems.
—Roger Hart
Director, Software Services
3DEC Version 2.0 Released ...............1 Modeling Hints..............................4
In the Spotlight .....................1 Linking Itasca Codes: Interactive
3DEC Applications ...................2 Analyses of Coupled 3D Problems .............5
Seismic Response of Stone Masonry Arches Recent 3DEC-Related Publications ..............7
State-of-Stress Determination SoftNotes...................................8
3DEC Arch Dam - Safety Analysis of Rock Foundation Training Corner .............................8
Soft Spot
3DEC Version 2.0 Released
tasca is pleased to announce the release of 3DEC Version
2.0. The new version of the code is specifically designed
for static, mechanical analyses in rock mechanics—and is
available at a price nearly half that of previous versions.
3DEC was created to model the quasi-static or dynamic
response to loading of rock media
that contain multiple, intersecting
joint structures. 3DEC simulates
large displacements, allows multi-
ple contact modes between blocks,
offers an explicit solution scheme,
provides multiple material models,
and can simulate excavation or
backfilling through the use of
“null blocks.” Tools available in
the code include a preprocessor
that reads AutoCAD files, interac-
tive manipulation of screen
images, mesh-generation tools, a
tunnel generator, and a statistically
based joint-set generator.
Features new to 3DEC with the release of Version 2.0
include the following items.
Built-in Programming Language FISH —The Itasca
programming language, FISH, enables users to define new
variables and functions to customize a numerical model to
suit their particular needs. FISH can vary block and joint
properties within the block structure, define variables for
plotting, implement joint generation schemes, apply a
servo-control of a numerical test, specify different boundary
conditions and automate parameter studies.
(Continued on page 6)
3DEC model of an arch dam
on a jointed rock foundation