1. 2D FEM Modeling of Seismic Wave Propagation in Coal Seam EGEE 520 Semester Paper Presentation By Hongliang Wang

2. Contents  Introduction  Governing Equations  Formulations  Solution  Validation  Parametric Study  Conclusions

3. Introduction  Mine Void Detection  In-Seam Seismic: Two-Dimensional Wave Propagation

4. Governing Equations  Conservation of momentum  Constitutive relation  Boundary conditions  Initial conditions

5. Formulation  Wave Equation  Boundary Condition

6. Solution  Transmission  Reflection Sensor and Source at different sides of the pillar Sensor and Source at the same side of the pillar

7. Validation “Law of reflection” Mine Void Detection Project

8. Parametric Study Attenuation vs. Frequency Stress wave attenuation F=10F=20

9. Conclusions  Two Dimensional Modeling appears to be a good approach for In-Seam Seismic wave propagation study.  FEMLAB is a good tool but need solid validation. If done carefully FEM can yield real insights.

10. Questions? I haven't failed; I’ve found 10000 ways that don’t work. ──Tomas Edison (1847-1931)