National Mineral Resources University (Saint Petersburg, Russia):

Tsirel S. V., Senior Researcher, Doctor of Engineering Sciences, e-mail: tsirel58@gmail.com

Pavlovich A. A., Post-graduate Student

«Gipronickel» Institute» LLC (Saint Petersburg, Russia):

Gaponov Yu. S., Engineer

Significant errors in assessment of expected seismic forces during the calculations of the pit edges stability are caused by the following factors:
-usage of integral values of earthquakes intensity, based on the set of general seismic zoning plans OSR-97 (ОСР-97);
-neglect of the standing term of pit edge.
According to this, it is necessary to use the differentiated approach during the assessment of seismic forces for a particular pit. This approach takes into account more exact (fractional) values of earthquakes intensity, based on the seismic microzoning. Allowable risk value and lifecycle of construction are also considered by this approach. The suggested methods are based on the determination of the lifecycle of pit edge, with application of the Taylor formula. This formula demonstrates the dependence of the time of pit development both from the amount of mineral reserves, and from the assessments of rate of open pit sinking in different directions, taking into account the differences in the slope angles of edges in operating and limiting positions. Seismic microzoning and assessments of probability of different intensity earthquakes, suggested by V. I. Ulomov, are used for the purpose of assessment of expected earthquake intensity in the place of pit location during the edges standing in the limiting position. In the absence of seismic microzoning, there is used the dual (temporal and spatial) linear interpolation, based on the A and B maps of the set of general seismic zoning plans OSR-97 (ОСР-97). This article presents the examples of calculations, made for Chernigovsky and Bachatsky coal pits in the territory of Kuznetsk Basin. These calculations show, that without the foregoing corrections, the error in detection of maximal earthquake accelerations can be 10-15% and higher.

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