PSI - Issue 32

E.A. Gubanova et al. / Procedia Structural Integrity 32 (2021) 42–48 E.A. Gubanova / Structural Integrity Procedia 00 (2021) 000 – 000

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displacement was based on analyzing the prospects for the formation of subvertical cracks in it. For the considered ideal elastoplastic medium, the relation between the deformations and stresses at the prelimiting stage was described by Hooke's law, and the ultimate stresses in the compression region were determined by the Mohr-Coulomb criterion, presented in the form of the classical form of the Mohr-Coulomb law by Kuznetsov(1947). In the tensile region, the ultimate stress was limited by the ultimate tensile strength. In the geomechanicalcomputations, the characteristics of the strength of the rocks that constitute the mass were corrected taking into account the coefficients of long-term strength for the salt rocks and softeningofthe rocks of the above-salt strata. As the numerical implementationmethod, we used the method of finite elements in displacements by Zienkiewichet al.(2013) with discretization of the considered area into triangular elements of the first order. The solution of the elastoplastic problem was based on the method of the initial stresses by Malinin(1975),Fadeev(1987). Based on the solution results at a certain instant of time, the final criteria-based estimation was obtained in the form of zones of technogenic destructions located in the area where the rock destruction in the compression area is caused by the shear cracks, as well as by the opening mode fracture in the tensile region. 3. Resultsof the Computations As for the geological section with the subhorizontal bedding of the seams typical for the Verkhnekamskoye deposit of potash and magnesium salts conditions (Fig. 1), we analyzed the influence of the mining operations during the extraction of sylvinite (KrII) and carnallite (V) compositions on safe conditions of the salt mass undermining with a further predictive criteria-based estimation of its sustainability. For a greater clarity of the results, the computation takes into account the areas of the reduced mechanical properties of the salt rocks in the form of seismic anomalies.

Fig. 1 . Design scheme of the geomechanical analysis

In the computations, we analyzed variations of the current geomechanical situation both with and without the