Deformation and damage to buildings caused by ground movements in mining areas (case study)

Abstract

Human activity causes transformations in the near-surface layers of the rock mass, which result in long-term impacts on buildings and engineering infrastructure. Mining activities are particularly disadvantageous in this context, as they trigger severe deformation processes that reach the soil surface as a result of the excavation of deposits. The prevention of accidents and disasters caused by these impacts is based on knowledge derived from observation. Therefore, the aim of this study was to acquire and update knowledge on the impact of mining-related ground deformation and tremors on buildings.  The paper presents the results of measurements carried out on a group of buildings located in an underground mining area. The buildings have been affected by mining impacts since their construction in the 1980s. Despite the implementation of appropriate structural protection, the structures have been suffering deformation and damage. For the purposes of the study, two two-axis inclinometers were installed on the 15.2 m high bell tower, taking measurements at 6-hour intervals. Over a period of 10 months, changes in the leaning of the tower were measured and the condition of the other buildings observed.
The study resulted in obtaining:

• values for the change in tilt of the two perpendicular walls of the tower (over a period of 10 months),
• correlation of the results with tremors measurements and periodic surveying measurements of the inclination of the vertical edge of the tower,
• image of damage to buildings caused by mining deformation of the ground.

On the basis of an analysis of the location and timing of minefields excavation, the occurrence of real ground movement in the mining areas, continuing even after the end of mining works, was confirmed and irregular deformation of the originally perpendicular walls of the masonry tower building was demonstrated. The tower did not behave as a rigid body; its horizontal profile was deformed.