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Date submitted2022-05-25
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Date accepted2023-02-02
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Date published2023-08-28
Evaluation of the shear strength of rocks by cracks based on the results of testing samples with spherical indentors
Experimental data on the relationship of the residual shear strength of rocks in closed cracks with the functional characteristics of intact rocks – the tensile and compressive components of adhesion, the roughness of the crack surfaces, and the level of normal stresses are presented. A unified integrated approach determines the shear strength of intact and destroyed rocks, the residual shear strength of closed rough cracks has been developed. The approach provides for the selection of stress intervals corresponding to different types of fracture, for each of which a strength criterion is proposed, expressed in terms of functional characteristics of intact rock. An express method for estimating the residual shear strength of rocks by cracks with a rough surface has been developed, in which an improved method of loading samples with spherical indentors is used as a basic test method. The express method implements the transition from the data of mechanical tests of samples with spherical indentors to the shear strength indicators for cracks in the rock mass, taking into account the level of normal stresses and the roughness of the crack surfaces measured in field conditions. In this case the roughness scale developed by Barton is used. The express method is informative and available in the fieldwork.
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Date submitted2020-12-02
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Date accepted2021-04-21
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Date published2021-06-24
Modeling the processes of deformation and destruction of the rock sample during its extraction from great depths
Article investigates the change in the geophysical properties of rocks in the process of extracting the rock sample from great depths. Evaluation of changes in effective elastic properties, porosity and permeability of rock samples during extraction was carried out by means of finite element modeling. Assessment of the critical dimensions and orientation of internal defects, leading to the destruction of the rock samples during extraction from great depths, has been made based on the methods of linear destruction mechanics. Approach that makes it possible to calculate the change in the mechanical properties, porosity and fracturing of reservoir rocks in the process of extracting the rock sample from depths to the surface is proposed. Use of refined data on the mechanical properties of recoverable rock samples makes it possible to increase the accuracy of digital geological models required for geological exploration, determination of reservoir properties and oil and gas saturation of a field, and development of oil and gas deposits. Application of such models is especially relevant at all stages of the fields development with hard-to-recover reserves.
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Date submitted2018-11-05
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Date accepted2019-01-01
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Date published2019-04-23
Features of elementary burst formation during cutting coals and isotropic materials with reference cutting tool of mining machines
- Authors:
- V. V. Gabov
- D. A. Zadkov
- Khac Linh Nguyen
The paper considers the cutting of brittle coals and rocks by a single cutter of a mining machine, in contrast to the generally accepted integral approach, different from the standpoint of the formation of successive elementary bursts that make up the cut. The process of the formation of an elementary bust in time is viewed as successive phases. Due to the complexity and multi-factor nature of the process, preference is given to experimental bench studies using reference cutters, isotropic materials, and real rock blocks. The bursting parameters values greatly influence the time of static forces action, the peculiarities of the formation of stress fields in the undercutter zone of the rock mass and the conditions for the emergence and development of main cracks in the near-cut zones during the cutting process. The accepted phase-energy method of analyzing the process, which most closely matches the structure of the studied process, revealed a more significant, than previously expected, effect on the cutting process, variability of cutting speed and potential energy reserve in the cutter drive. The paper discusses the possibility of purposeful formation of the parameters of elementary bursts. It describes new ways to improve the efficiency of cutting coal and rocks, in particular, reducing the maximum loads and specific energy consumption. It also considers the possibility of reducing the grinding of the rock mass and dust formation.
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Date submitted2014-12-07
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Date accepted2015-02-23
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Date published2015-12-25
Bump hazard evaluation of a rock mass area as a result of its seismic acoustic activity registration
- Authors:
- V. V. Nosov
Ore production in deep rock-bump hazardous mines is closely connected with the need to in-crease workers’ safety, which demands heavy costs of taking preventive shockproof actions and applying expensive protection systems against mountain blows. The article considers a resource forecasting technique and a bump hazard evaluation method for a rock mass area, based on a mi-cromechanical model, which registers acoustic emission of heterogeneous materials, and empirical data, obtained as a result of acoustic signals registration with the help of the model, aimed at seis-mic-acoustic activity evaluation at «Taimir» and «Oktyabrsky» rock mass areas, belonging to Norylsk industrial region.
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Date submitted2009-09-10
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Date accepted2009-11-18
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Date published2010-06-25
Numerical modelling of shear strain near to the crack
- Authors:
- S. E. Mansurova
The behaviour of a material near to a crack is considered at nonlinear shear strain. The plane problem of the nonlinear theory of elasticity in the variation form is solved. Some variants of boundary conditions are used. The numerical results received by a finite element method are presented.
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Date submitted2009-08-03
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Date accepted2009-10-30
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Date published2010-02-01
Geotechnical engineering features of the estimation of stability of heavy constructions of designed cement works in Novorossiysk
- Authors:
- Yu. V. Khaliullina
In the paper possibilities of constructing industrial heavy structures near slopes are described. The influence of tectonics, seismicity, a relief, deposit rocks thicknesses, their physical properties of geotechnical engineering feature are analyzed. The law of marls durability change is established. Positions of the most probable surfaces of sliding in cracked monoclonal deposit thickness are shown. The estimation of stability of the loaded slopes is made. Some recommendations for maintenance of structure stability are given.