PSI - Issue 32

A.A. Baryakh et al. / Procedia Structural Integrity 32 (2021) 109–116 A.A. Baryakh et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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(10) At the Gremyachinskoye field, the waterblocking stratum includes the Upper rock salt, an anhydrite-dolomite stratum, and the Lower rock salt overlying the sylvinite layer being mined. The anhydrite-dolomite stratum is anhydrous but does not represent a zone of water confinement due to the presence of natural jointing. Thus, the formation of the trough zones of jointing (plasticity) in the interval between the Lower and Upper rock salt layers is the criterion for the loss of stability of the waterblocking stratum. The estimation of the state of the waterblocking stratum was carried out at various points in time, including at the time of completion of the displacement process, when the maximum destruction of the underworked mass was recorded (Fig. 5). Indeed, the Lower rock salt and anhydrite-dolomite strata were subject to destruction. The upper rock salt layer completely retained its continuity and protected the mine from fresh water breakthrough into the mine workings. The obtained results confirm that with an increase in the mining depth, the risk of destruction of rocks in the waterblocking strata decreases, as previously noted by Baryakh et al. (2012).

Fig. 5. The nature of the technogenic discontinuity of the waterblocking stratum at the endof the displacement process

The presented prediction estimates are preliminary, since they were obtained during the initial stage of the field mining without sufficient experimental data and should be refined since field measurement data and observations of the rock mass deformation worked at great depths are still being accumulated. 5. Conclusions 1. A means of calibrating the geomechanical model considering new potash salt deposits being prepared for mining has been presented according to data about the development of the displacement process in similar deposits with its subsequent correction. This reflects a certain difference in the geological structures and parameters of the mining system.