68000 Element Problem

68000 Element Problem

This example demonstrates a complex model with ground surface, an open pit, underground mining and several layers of alternate materials in the hanging-wall. Contours of the major principal stress are shown on a horizontal cutting plane.

The model was constructed with 6125 surfaces and subsequently discretized into 67825 boundary elements thus requiring over 200000 degrees of freedom. 14268 grid points were calculated for display of the results. Due to efficient lumping, the matrix size required for this analysis was only 2.1 GBytes.

In this example, the ground surface and open pit were constructed using FF (fictitious force) elements, although they could also have been build using DD (displacement discontinuities) is desired. The thicker parts of the underground mining have also been built using FF elements while the some of the thinner sections were built using DD elements. The alternate material zones have been constructed using both FF and DD zones and have been filled with softer weaker material. This allows these zones to behave in a ductile manner and yield where they are overstressed.