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Date submitted2023-06-01
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Date accepted2024-03-05
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Date published2024-08-26
Analyzing friction bolts load bearing capacity in varying rock masses: an experimental study in Anti Atlas Imiter silver mining region, Morocco
This study analyzes how key factors impact friction rock bolt capacity using standard pull-out tests, focusing on 39 mm diameter, 180 cm long split-tube bolts. We investigate bolt performance dependence on rock mass rating (RMR), time after installation, schistosity orientation, surface roughness, and installation quality. The aim is optimizing bolt design and implementation for enhanced underground stability and safety. Results show RMR strongly exponentially correlates with pull-out resistance; higher quality rock masses increase capacity. Anchorage capacity significantly rises over time, especially for RMR above 70. Increasing angle between bolt axis and rock foliation from 0 to 90° boosts pull-out response. Reducing borehole diameter below bolt diameter grows bolt-ground friction. Empirical models estimate load capacity based on RMR, time, orientation, diameter, roughness and installation quality. These reliably predict bolt performance from site conditions, significantly improving on basic RMR methods. Experiments provide practical friction bolt behavior insights for typical rock masses. The data-driven analysis ensures models are applicable to actual underground scenarios. This enables tailored optimization of bolting configurations and supports. Methodologies presented should improve safety, efficiency and cost-effectiveness of reinforced mining and tunneling. Overall, this study fundamentally furthers friction bolt performance understanding, enabling superior underground support design.
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Date submitted2020-05-24
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Date accepted2020-05-29
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Date published2020-06-30
Features of permeability anisotropy accounting in the hydrodynamic model
Important step in the construction of a geological and hydrodynamic model is to set the correct properties of the formations and further adapt the model to the historical development data. Main source of information on the geological properties of reservoirs is well logging data. Paper describes the application of the method for post-interpretation processing of logging data, with the help of which the lateral anisotropy value of the field site is found. Brief discussion on the algorithm for adapting the hydrodynamic model to the parameters of the formation using one reference well is given. Feature of the logging data application to study the phenomenon of permeability anisotropy is that this type of research is widespread, has sufficient information content, and the geophysical system itself does not require the inclusion of specialized instruments. Based on geophysical study, a volumetric model of the properties for oil and gas bearing formation is constructed, from which the permeability distribution is used, whose gradient allows establishing the directions of improved and deteriorated filtration properties. As a result, during adaption of the model, it was possible to achieve a difference in reserves between the geological and hydrodynamic models of 2.4 %, which is an acceptable deviation for further calculations. It was found that the direction of improved filtration properties has a northeastern direction at an angle of 35°, and the value of lateral anisotropy is 2.2. Obtained results of lateral anisotropy, taking into account the data on values of vertical anisotropy, are included in the field model, where it is planned to further study the effect of permeability anisotropy on formation productivity.
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Date submitted2020-06-11
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Date accepted2020-06-11
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Date published2020-06-30
Improving the geological and hydrodynamic model of a carbonate oil object by taking into account the permeability anisotropy parameter
- Authors:
- Dmitry A. Martyushev
Significant share of the developed oil assets related to carbonate complex-built objects has formidably increased in Russia, including the Perm Region. Reliable knowledge of the parameters for the cavern-pore type of the reservoir allows clarifying the existing geological and hydrodynamic models (GHM), selecting a rational development system, regulating the development processes and providing optimal geological and technical measures for this formation. In the construction and adaptation of GHM for oil fields, especially those related to complex-built carbonate reservoirs, knowledge of both horizontal and vertical permeability (anisotropy parameter) is important. When creating GHM of carbonate objects in Perm Region deposits, vertical permeability is often taken to be zero, although this is far from being the case. Determining the vertical permeability (anisotropy parameter), its dynamics when changing the formation and bottomhole pressures and using it in GHM is an urgent task that will improve the quality and reliability of using digital models to calculate and predict the oil production process. Article describes the methodology for determining permeability anisotropy according to the interpretation of hydrodynamic investigations of wells. Proposed methodology for determining the anisotropy parameter processed the results of more than 200 studies conducted on production and injection wells of the Famennian deposit at the Gagarinskoye field. For each lithological-facies zone, dependence of the permeability anisotropy index on the bottomhole pressure is constructed. To predict and evaluate the effectiveness of the applied geological and technical measures and technological development indicators, author modified the geological and hydrodynamic model taking into account the obtained dependencies on the change in the anisotropy parameter. Using a modified hydrodynamic model, it was possible to significantly improve the adaptation of both production and injection wells. Thus, the quality and reliability of the digital model of the Famennian deposit at the Gagarinskoye field for calculating and predicting the oil production process has improved.
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Date submitted2016-09-03
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Date accepted2016-11-24
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Date published2017-02-22
Research of compression strength of fissured rock mass
- Authors:
- A. G. Protosenya
- P. E. Verbilo
The article examines a method of forecasting strength properties and their scale effect in fissured rock mass using computational modelling with final elements method in ABAQUS software. It shows advantages of this approach for solving tasks of determining mechanical properties of fissured rock mass, main stages of creating computational geomechanic model of rock mass and conducting a numerical experiment. The article presents connections between deformation during loading of numerical model, inclination angle of main fracture system from uniaxial and biaxial compression strength value, size of the sample of fissured rock mass and biaxial compression strength value under conditions of apatite-nepheline rock deposit at Plateau Rasvumchorr OAO «Apatit» in Kirovsky region of Murmanskaya oblast. We have conducted computational modelling of rock mass blocks testing in discontinuities based on real experiment using non-linear shear strength criterion of Barton – Bandis and compared results of computational experiments with data from field studies and laboratory tests. The calculation results have a high-quality match to laboratory results when testing fissured rock mass samples.
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Date submitted2015-12-29
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Date accepted2016-02-21
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Date published2016-12-23
Poorly studied phenomena in geoelectrics
- Authors:
- V. S. Mogilatov
Undoubtedly, modern geoelectric technologies emerge in the result of the development of traditional approaches and techniques. However of more interest is the appearance of completely new technologies based on new effects and new models of interaction of geological medium and electromagnetic field. The author does not commit to indicate principally new directions, but only wants to discuss some poorly known facts from the theory and practice of geoelectrics. The outcome of this study could be considered attracting the attention of experts to non-traditional signals in geoelectrics. The reviewed phenomena of interest, not fully implemented in practice in the author’s opinion, are field split into two polarizations: transverse electric (the ТЕ-field) and transverse magnetic (the ТМ-field), then some poorly known properties of ТМ-field, the role of bias currents, the anisotropy of horizontal resistances, the role of geomagnetic field in geoelectric sounding, the unique resolution of CSEM (Controlled Source Electro-Magnetic) techniques at sea.
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Date submitted2015-12-13
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Date accepted2016-02-23
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Date published2016-12-23
Properties isotropy of magnesium alloy strip workpieces
- Authors:
- R. Kavalla
- V. Yu. Bazhin
The paper discusses the issue of obtaining high quality cast workpieces of magnesium alloys produced by strip roll-casting. Producing strips of magnesium alloys by combining the processes of casting and rolling when liquid melt is fed continuously to fast rolls is quite promising and economic. In the process of sheet stamping considerable losses of metal occur on festoons formed due to anisotropy of properties of foil workpiece, as defined by the macro- and microstructure and modes of rolling and annealing. The principal causes of anisotropic mechanical properties of metal strips produced by the combined casting and rolling technique are the character of distribution of intermetallic compounds in the strip, orientation of phases of metal defects and the residual tensions. One of the tasks in increasing the output of fit products during stamping operations consists in minimizing the amount of defects. To lower the level of anisotropy in mechanical properties various ways of treating the melt during casting are suggested. Designing the technology of producing strips of magnesium alloys opens a possibility of using them in automobile industry to manufacture light-weight body elements instead of those made of steel.
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Date submitted2014-12-25
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Date accepted2015-02-07
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Date published2015-12-25
Nondestructive control of elasticity modulus anisotropy of composite materials in the products
- Authors:
- A. I. Potapov
The technique of nondestructive control of anisotropy of composite materials in a product us-ing a pulse ultrasonic method is considered in the article. Calculated dependence to determine the degree of filler orientation in a polymeric composite material with varying filler laying is shown. The following filler laying is considered: chaotic, longitudinally cross, unidirectional. In addition, experimental results of anisotropy control of the elastic modulus in glass-reinforced plastics with different degrees of anisotropy using the pulsed ultrasonic method are given in the article.
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Date submitted2009-07-26
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Date accepted2009-09-10
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Date published2010-04-22
Mathematical modeling of deformation processes and failure in fractured rock mass
- Authors:
- A. G. Olovyanny
The paper presents the developed modeling program of geomechanical processes in fractured rock mass. In modeling one took into account the geometry of the mined-out space varying in the process of mining operations. Deformation and failure of rocks are modeled on directions with due account of varying anisotropy of deformational and strength properties. As a result, modeling enables to determine not only the fields of stresses and deformations, but also the failure zones and degree of strength attenuations and their orientation. An example of modeling of layer failure development of enclosing rock mass during mining of stratified deposit is included.