The specificities of deformations and failures of highly stressed hard rock massifs

Anatolii Kozyrev,Nikolay Kuznetcov,Eduard Kasparyan,Iuliia Fedotova,M Guzev,I Rasskazov,V Makarov

doi:10.1051/e3sconf/201912901010

Anatolii Kozyrev, Nikolay Kuznetcov + Show 5 more

Open Access

https://doi.org/10.1051/e3sconf/201912901010

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Abstract

According to modern concepts, the state of highly stressed hard rock massifs is mostly caused by the effect of gravitational-tectonic stress fields. At that, a probability of brittle rock failure in a dynamic form is very high. Such failures are always accompanied by the significant energy release accumulated during the deformation process. Based on the experimental studies of deformation and failure processes in various types of rock samples from the Kola Peninsula deposits, we have proposed the criteria for classifying rocks as prone to rock bursts. The information for assessing the rock proneness to dynamic failures can be obtained by analysing the strain curve at the pre-peak section when tested on the ordinary presses and testing devices according to the standard methods. If we study the processes of rocks' deformation and energy accumulation under the triaxial loading mode, we can establish the parameters for the occurrence of dynamic failure of rocks. This, in turn, will allow identifying the conditions of such failure in the investigated rocks for a specific mining-engineering situation and, thereby, coming to a scientifically-based prediction of the rocks' proneness to dynamic rock pressure occurrences.

Highlights

Intensive and large-scale activity of mining enterprises in the underground mining of rockburst-hazardous deep seated ore deposits affects the change in mechanical stresses in the upper part of the earth's crust. These changes are accompanied by irreversible geomechanical processes and dangerous geodynamic phenomena
The problem to predict of the dangerous geodynamic phenomena is an urgent and complex task, due to many factors and causes of their manifestation, geological and technological conditions of mining
In hard rock massifs under the action of gravitational-tectonic natural stress fields, the rock failure occurs often in the dynamic mode with the energy release accumulated during previous deformation. This is the cause of numerous seismic events which are constantly registered in the hard rock massifs and occur in the mines as rock bursts with different intensity

Summary

Introduction

Intensive and large-scale activity of mining enterprises in the underground mining of rockburst-hazardous deep seated ore deposits affects the change in mechanical stresses in the upper part of the earth's crust These changes are accompanied by irreversible geomechanical processes and dangerous geodynamic phenomena (rockburst and tectonic bumps, mining induced seismicity). In hard rock massifs under the action of gravitational-tectonic natural stress fields, the rock failure occurs often in the dynamic mode with the energy release (often in significant amount) accumulated during previous deformation. This is the cause of numerous seismic events which are constantly registered in the hard rock massifs and occur in the mines as rock bursts with different intensity. The state of knowledge of these reasons is quite different

The method for estimating the rock proneness to a dynamic failure

The specificity of gravitational-tectonic stress fields

The ways to solve the problem of prediction of dynamic failures

Findings

Conclusions