Hardening soil model in prediction of plastic deformation zone in soft rock mass of Yakovlevo iron ore deposit

Abstract

The authors propose a sizing procedure for the zone of plastic deformation (possible failure) in rock mass in the vicinity of stoping using the method of numerical modeling and the Hardening Soil Model (HSM). The relevance of HSM application in the conditions of Yakovlevo deposit is confirmed, among other things, by the dependence of the deformation modulus of rocks in the volumetric stress state on the effective stresses. The subject of research is the Yakovlevo deposit of high-grade iron ore, which holds the largest reserves in the Belgorod Region of the Kursk Magnetic Anomaly. Stoping and mine support operations induce continuous rock falls and caving because of the unreliable prediction of rock mass stability in the vicinity of stoping and due to the low strength of enclosing rock mass. Selection and validation of HSM parameters for iron–mica–martite ore of Yakovlevo deposit included processing of laboratory testing results obtained using equipment of the Saint-Petersburg Mining University. The triaxial tests of ore samples at different values of lateral pressure were computationally reduced to a reference abutment pressure value pref set by the software designer. The numerical experiments and virtual testing of the material behavior model, as well as the justification of the possible failure zone size were implemented in the certified software environment Bentley Systems PLAXIS-3D. Finally, on the basis of the integrated research of different-density ore samples, including laboratory tests and numerical experiments, the rock mass behavior models are constructed and the parameters of plastic deformation zones (possible failure) in the vicinity of a single stone are predicted.The study was supported under the state contract for scientific work in 2021, Grant No. FSRW-2020-0014.