A coal mining example

This example demonstrates a shallow coal mining example. The model includes 5 different material strata with simulation of ground surface. 6 mining steps were used to study the stress redistribution as mining progressed.

The model was constructed with 431 3D blocks using FF (fictitious force) elements to describe the various excavations and alternate material zones. 1 DD (displacement discontinuity) element was used to describe the ground surface. From this data, Map3D generated 1983 surfaces and subsequently discretized these into 31082 boundary elements, thus requiring almost 100000 degrees of freedom. 46173 grid points were calculated for display of the results. Due to efficient lumping, the matrix size required for this analysis was only 1.2 GBytes.