Features of structural assessment of long life mine shafts

Abstract

The issues of restoration and reconstruction of mine shafts become of increasingly higher concern these days. Timely accomplishment and complex safety are the first-order conditions of the successful project implementation. The existing regulatory documents in this sphere are inexhaustive. In this respect, and integrated approach is proposed, including geophysical investigation of shaft siding areas, experimental estimation of load-bearing capacity of support systems, experimental computations using 3D finite element method, as well as the analysis and prediction of structural reliability. The authors exemplify implementation of the complex approach. The GRP measurements and seismic research in some shafts revealed long intervals of fractured rocks and damaged rock/lining interface zones, as well as local voids in the space behind the lining. These data were used to adjust mathematical models with the identification of local zones in the fractured shaft side rock mass with low deformation characteristics, and some series of calculations were performed. In the test area of a mine shaft, the calculations and the in-situ measurements of stresses and deformations agreed sufficiently. The authors highlight that the research-based data array enables better reasoned decision-making on design, construction and technology at integrated safety and enhanced efficiency of operations. Moreover, understanding of the actual condition of the shaft lining and adjacent rock mass can help avoid causeless repair which decreases load-bearing capacity of shaft support down to extreme values in the short run, and continually ends with incidents and large accidents in actual practice.