Biot-Rayleigh theory Comunismo Historia History of engineering & technology Política y gobierno Sun, Jianping Technology: general issues amplification effects cemented coal gangue-fly ash backfill sample compression test concrete lining structure crushed rocks deformation characteristics directions of incident waves dynamic contact force equivalent nodal forces fault dislocation ground motions kaolin lateral stress macroscopic failure mechanical properties microcrack porosity microstructure non-pillar coal mining rock-physics template seismic damage analysis seismic deterioration effect slope topography tight sandstone gas reservoirs