Analysis of Mining Influences on a Small Frame Railway Viaduct

In the article, the example of the rebuilding of the real bridge object shows, how to take into account the impact of mining area deformations on small frame railway viaducts integrated with the embankment. General principles are given, how to determine additional forces induced in the construction, such forces arise as a result of mining deformations on the surface of the area. It is discussed, how to shape the geometry of the bridge structure, so that in the future it will be possible to raise the level of the railway track even by several meters (in order to eliminate the local mining hollow), without rebuilding of the viaduct. Attention is paid to the necessity of shaping the foundations so that the impact on the subsoil tension under the embankment and under the viaduct is the same, so that the viaduct can settle in the same way as the adjacent railway embankment. In addition, technological aspects related to the adjustment of the viaduct to ground conditions (shallow, thin layers of cohesive-plastic soil typical for post-glacial areas in Poland on Silesia Upland) and protection of railway traffic continuity through a bridge type relieving construction are shown. The article is supplemented by the results of 8-years measurements of subsidence and displacements of the viaduct on the deforming mining ground and conclusions from observations. This method of analysis and conclusions may be used in further studies of the interaction between the embankment and the viaduct embedded in the embankment in the situation of active mining deformations of the area.