Influence of Underground Mining on Ground Surface and Railway Bridge Under Thick Alluvium

1 Introduction Ground surface movements, induced by under- ground mining as a kind of man-made geological ca- tastrophe, has been a major issue of geoenvironmental concern1]. These not only destroy farm land and building structures but also influence the biological environment. Study of the pattern of mining-induced ground movements and its variation over time is very important for the protection of buildings. Up to now, some patterns of ground movement over mining areas have been known, but …

Influence of Underground Mining on Ground Surface and Railway Bridge Under Thick Alluvium

Patterns of ground movement and pore water pressure variation are obtained through a case study using a finite element method. With the progress of excavation, ground subsidence, ground inclination and horizontal displacement accelerates, Along the striking direction, a subsidence basin is formed on the ground surface induced by underground mining. The maximum subsidence is around 5.41m. The ratio of ground subsidence to the thickness of the coal seam is 1.08. The maximum inclination is 11.5 mm/m. The maximum horizontal displacement is 2.15 mm/m. At the time the coal has been excavated, the maximum pore water pressure reaches 25 kPa. In order to improve protection of structures located over the area with underground mining, the variation of additional stresses of a railway bridge induced by ground surface deformation is analyzed. The main effect of underground mining on the railway bridge is the tensile stress and the maximum value reaches as high as 4.29 MPa, which is greater than the concrete tensile strength.