PSI - Issue 32

120 I S Lomakin et al. / Procedia Structural Integrity 32 (2021) 117–123 I S Lomakin, A A Tsayukov / Structural Integrity Procedia 00 (2019) 000 – 000 where is the coefficient taking into account the load changes on the pillars due to an influence of various mining and technical factors (when loading from salt dumps, support pressure, the presence of interpass pillars, etc.); is the bulk weight of the rocks; H 0 is the maximum value of the distance from the earth surface to the roof of the pillars; a is the width of the stopes; b is the width of the interchamber pillars; k f is the form factor of the pillars; is the rock strength in the mass. 4

Fig. 1. Schematic diagram.

The quantitative correspondence between the loading degree of the interchamber pillars and the invariants of their stress state was substantiated in (Baryakh et al. 2007), where the energy criterion was taken as a condition for the strength of the salt rocks ൌ ≤ ͳ (4) In equation (4) σ  is the aggregate strength of the rocks in the mass, σ ‹ ൌ ʹ ሺ ሻ is the intensity of the shear stresses determined by the value of the second invariant of the stress deviator. The calculations have shown a good correlation of the loading degree of the pillar with the value of parameter ∗ acting along the whole width and height of the pillar (Baryakh et al. 2007): ≈ ∗ (5)