3DEC
includes the ability to simulate fluid flow through joints. The
calculations are fully coupled such that pressure changes can cause
displacements of the solid. However, often we don’t want to deal with
the complexity of modelling fluid flow through joints, or even modelling
fluid flow at all.
3DEC also therefore provides a much simpler approach to considering
pore pressures. A water table can be specified (as a simple plane, or
an imported surface geometry) and pore pressures are calculated at the
centroid of each zone based on the depth below the water table, the
water density and gravity. The pore pressures are then used to
calculate effective stresses in the zones. The effective stress is then used when checking if the material strength has been exceeded.
Unlike in UDEC, pore pressure changes have no effect on the total
stress in 3DEC. What this means is that if the water table is raised or
lowered, no deformation will be observed (unless material strength has
been exceeded). To account for changes in total stress, the user must
use a FISH function to manually change the zone stresses based on pore
pressure changes.
The plots below show a simple block that is initially dry. The water
table is then raised to the top of the block. By using the fish
functions to adjust the total stress, you can see the heave of the
material due to the increased pore pressures. The data file and fish
functions to execute this example are given here: ats.zip
Seamless Integration of Site Data for Improved Mining Analysis Now Available for IMAT: Seamless Integration of Site Data for Improved Mining Analysis... Read More
Now Available from ITASCA: Innovative Machine Learning Tool for FLAC3D/FLAC2D V9.2 Experience the Future of Geotechnical Modeling with ITASCA Software V9.2: Introducing Machine Learning Models... Read More
Experience the Future of Geotechnical Modeling with ITASCA Software V9.2 Experience the Future of Geotechnical Modeling with ITASCA Software V9.2: Introducing Machine Learning Models and... Read More
Upcoming Events
23Sep
Getting Started with FLAC2D/FLAC3D
Live Online Introductory Training Course.
September 23-24, 2025....
Read More
14Oct
Getting Started with 3DEC
Live Online Introductory Training Course.
October 14-15, 2025...
Read More