Abstract
Purpose. The research aims to conduct a comprehensive study of the mechanical properties of ores and rocks within the Zhilandy Group field, as well as to assess the natural field of mass stress state to solve geomechanical problems in optimizing mining operations. Methods. To determine the boundary conditions when measuring the stress-strain state of the mass, a complex methodology is proposed, including stress measurements using hydraulic fracturing methods of the wells and determining the physical-mechanical properties of rocks. Five rock probes have been tested. Twelve tests (six tests in natural and six in water-saturated states) have been conducted for each probe. Findings. Hydraulic fracturing tests at the metering stations show significant tectonic stress due to the shape of structural folds and the mass fracturing. It has been revealed that the hard rock mass is characterized by non-uniform fracturing. It is of tectonic origin and averages between 10-15 and 15-25 fractures per meter for different lithological varieties. The maximum horizontal stress at the stations is oriented along an azimuth of 70° ± 10. Originality. The influence of water saturation on the reduction of strength and deformation characteristics of rocks has been determined for the conditions of the Zhilandy Group field, which shows significant variations depending on the rock type. Especially important is the revealed fact of a significant decrease in uniaxial compression and uniaxial tensile strength, as well as a decrease in Young’s modulus and cohesion factor. Linear dependences of stresses occurring with depth have been obtained from the measurement results. Practical implications. The results obtained are of significant importance for the mining industry. Understanding the extent of reduction in strength characteristics during water saturation and assessing the natural field of the stress mass state allows more accurate prediction of rock behavior.
Publisher
Dnipro University of Technology