Prediction of strain in a shaft caused by underground mining

Displacements and strains due to mining can lead to damage to objects on the terrain surface and in the rock mass. Due to their importance, the functionality of main shafts of a mine must be secure. In order to make these shafts secure mining within their surroundings is limited or carried out by special methods. Continuous displacements due to a mining activity are forecast by means of the Knothe method with amendments. This method is used in case of both objects on the ground surface, and mine shafts. Commonly horizontal and vertical strains are determined separately. In order to assess threats to shafts due to continuous displacements, one should determine main spatial displacement along the entire shaft tube. This work presents a method to determine the main spatial deformations (3D). Results and discussion are illustrated on an example.

► Shafts' functionality must be satisfied throughout the duration of the mine.
► Alternative prediction of deformation can optimise safety exploitation around shaft.
► It is necessary to calculate the spatial strain (3D).
► Main values of strain tensor and their direction can be calculated with geometrical method.
► Main values of spatial deformations should determine designed mining around shaft.