Geomechanical prerequisites for developing underground critical infrastructure based on the experience of deep mine operation

Abstract

Purpose. To substantiate the use of established mine-geomechanics regularities as a scientific basis for assessing the stability of prospective underground and deep-buried critical infrastructure facilities.

Methods. The study combines analysis of regulations on critical infrastructure protection, synthesis of theoretical and field studies of geomechanical processes around deep mine workings, and dimensionless analysis. The comparison of underground facilities of different purposes, scales and depths accounts for the natural stress state, strength and deformation properties of the geomaterial, contour displacement, relative depth, stress-field non-uniformity, water saturation and supporting-structure stiffness.

Findings. A system of dimensionless criteria for partial geomechanical similarity between deep mine workings and shallow underground structures has been developed. The computational example establishes that facilities with substantially different absolute stresses and geomaterial properties may have similar degrees of strength mobilization σ₀/Sₘ and relative deformability σ₀/Eₘ. However, similarity in these criteria does not ensure complete geomechanical similarity: as H/R decreases, the influence of the free surface becomes increasingly important, so the deformation mechanism of a shallow structure differs from that of a deep excavation.

Originality. The dependence of partial geomechanical similarity on a set of dimensionless parameters characterizing strength mobilization, deformability, relative depth, stress-field non-uniformity, water saturation and relative stiffness of the supporting structure has been established. A regularity is identified whereby convergence of σ₀/Sₘ and σ₀/Eₘ for a deep excavation and a shallow structure indicates similarity in strength mobilization and deformability, whereas a substantial difference in H/R limits such transfer because of the increasing influence of the free surface.

Practical implementation. The criteria make it possible to identify which field observations and verified models of mining geomechanics can serve as an initial basis for stability analyses of new underground facilities. The approach does not replace site investigations, numerical modelling or code-based design of a specific structure.