Field Investigation and FEM Analysis of Ground Subsidence in a Chinese Underground Gold Mine

Ground subsidence in a Chinese underground gold mine is remarkable. To find out reasons and regularities of the subsidence, following research work was carried out: (1) systemetical investigations of engineering geological conditions, including in situ stress state, location and size of old river beds, ponds and unfilled mined-out areas, (2) in situ monitoring of strata movement by multi-point extensometers in 3 vertical boreholes; (3) FEM (Finite Element Method) analysis to study the relationship between the ground subsidence and mining excavation, especially to inspect the influence of unfilled mined-out areas at shallow depth on the subsidence. Based on the research results, measures to control the ground subsidence and to prevent buildings from damage are provided.