scholarly journals Scientific and technical aspects of grouting of marginal rocks of mine workings

2020 ◽  
Vol 168 ◽  
pp. 00057
Author(s):  
Serhii Musiienko ◽  
Tetiana Palamarchuk ◽  
Liliia Prokhorets ◽  
Volodymyr Kurinnyi
Keyword(s):  
Concrete Structures ◽  
Operating Conditions ◽  
Rock Massif ◽  
Plunger Pump ◽  
Technical Aspects ◽  
Structure System ◽  
Maximum Radius ◽  
Roadway Safety ◽  
Mine Workings

The goal of the paper is to justify ways to achieve maximum radius of extent of grouting mortar in a rock massif and to maximize filling of cavities and cracks with minimal openings. Filling of cavities and cracks directly influences a “massif – roadway – safety structure” system. Some scientific and technical aspects of grouting and injecting inorganic binders into marginal rocks are considered. Advantages of usage of triple plunger pumps in injecting units are determined. The influence of pulsation on a condition and process of grouting mortar extension is justified. It is established that under equal operating conditions, pulsations created by a triple plunger pump reduce mortar viscosity by 15 %, and a radius of extent of mortar based on grouting cements is increased by an average of 12 %, and with usage of very finely dispersed substances – up to 20 %. Suggested recommendations significantly improve the technology of grouting of marginal rocks and concrete structures.

scholarly journals Development of Technological Schemes for Conducting Mine Workings with the Use of an Anchorage with Allowance for the Stressed State of the Rock Massif

2018 ◽  
Vol 155 ◽  
pp. 01031
Author(s):  
Alexander Tomilov ◽  
Nadezhda Tomilova ◽  
Assiya Batyrkhanova
Keyword(s):  
Stressed State ◽  
Rock Massif ◽  
Structural Scheme ◽  
Effective Technology ◽  
Highly Effective ◽  
Mine Workings

The article presents a structural scheme for solving the problem of creating a highly effective technology for conducting and supporting preparatory workings, consisting in establishing the laws governing the development of geo mechanical processes for the development of rational technological schemes for conducting mine workings with anchorage. The order of development of technological schemes of carrying out of mine workings with application of an anchor fastening taking into account the intense condition of a file of rocks is generated.

scholarly journals IMPROVING THE OPERATIONAL RELIABILITY OF HYDRAULIC FACILITIES WHEN USING POLYMER AND POLYMER-CEMENT COMPOSITES

2019 ◽  
pp. 217-230
Author(s):  
O. V. Kovalenko
Keyword(s):  
Composite Materials ◽  
Environmental Factors ◽  
Concrete Structures ◽  
High Strength ◽  
Cement Composite ◽  
Operational Reliability ◽  
Operating Conditions ◽  
Hydraulic Structures ◽  
Water Reclamation ◽  
Technical Solutions

Actualuty of the problem. The effective functioning of water-reclamation systems depends to a large extent on the operational reliability and durability of hydraulic structures. The structural elements of hydraulic structures of water management and reclamation complex from the moment of commissioning are subject to aggressive environmental influences. Aggressive factors (hydrostatic water pressure, alternating freezing and thawing, wetting and drying, corrosive action of salts dissolved in water, dynamic action of ice, etc.) constantly affect concrete structures, gradually destroying them. Therefore, the development of measures aimed at ensuring high resistance of structures to the aggressive environmental factors is relevant. Effective operation of structures with long-term aggressive environmental factors is only possible if they are protected (reinforced) with effective insulating, anticorrosive, high-strength, wear-resistant and cavitation-resistant composite materials. Specific characteristics of polymer and polymer-cement composite materials (high strength, corrosion resistance, frost resistance, adhesion to different coatings) enable to create effective technologies for restoring the functional capacity of hydraulic structures and increasing their stability. The need of reinforcing concrete structures of hydraulic facilities by combining or partially replacing them with modern composite materials and structures made of polymers and polymer cement is determined in view of increasing coolness, reliability and durability of the structures. These materials should be standardized at the stage of design, construction, repair and reconstruction of structures that will ensure their operational reliability and durability in aggressive environment. The development and implementation of technical solutions increasing the operational reliability and durability of hydraulic facilities for water-reclamation purposes while reducing their material and metal intensity are ones of the main areas of scientific research in the field of construction, repair and reconstruction of water-reclamation systems. Achieving high technical and economic performance of hydraulic facilities, taking into account the significant effect of aggressive environmental factors on them is possible using a scientifically sound combination of concrete and reinforced concrete structures with polymer and polymer cement composite materials. The highest level of reliability will be ensured by the structures providing the protection against damage, corrosion and filtration using the latest high performance composite materials. Optimization of technical solutions to increase the operational reliability and durability of hydraulic facilities is only possible provided that modern composite materials properties are comprehensively studied, their compliance with the requirements of water and reclamation construction, taking into account extreme operating conditions, is determined and new efficient technologies for future performance of the facilities are created. Along with expanding the use of polyme and polymer-cement composite materials, finding new varieties of polymer additives and obtaining reliable data on the durability of these materials in different operating conditions will be extended. Results. The Institute of Water Problems and Land Reclamation of NAAS has developed the main technological areas of polymer and polymer-cement composite materials application for increasing the operational reliability of hydraulic structures of water management and reclamation complex: polymeric film screens and geomembranes for increasing the anti-filtration properties; polymer and bitumen-polymer sealants for the arrangement and restoration of deformation joints; polymer and polymer-cement mixtures for structural repairs, restoration of bearing capacity, waterproofing protection, protection against filtration, accidental damage, corrosion, cavitation and actuation of hydraulic structures; concrete polymers, polymer concrete and polymer cement with high physical and mechanical properties for construction, repair and reconstruction of hydraulic structures.

Effect of the ITZ Damage on Durability of Reinforced Concrete in Chloride Environment

1994 ◽  
Vol 370 ◽  
Author(s):  
Raoul François ◽  
Ginette Arliguie
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Concrete Structures ◽  
Operating Conditions ◽  
Reinforced Concrete Structures ◽  
Actual Operating ◽  
Chloride Environment ◽  
Concrete Elements ◽  
Transfer Properties ◽  
Salt Fog

AbstractThis paper deals with the effect of the ITZ on the service life of reinforced concrete. In the case of reinforced concrete structures, the penetration of chlorides does not depend only on concrete transfer properties but also on the loading applied, on the state of strains and on the exposure to the aggressive environment.In order to take into account these different parameters, we have performed experiments on reinforced concrete elements, over a long period. The samples used have to be of an adequate size (3 meters long) and stored in a salt fog in a loading state so as to be representative of the actual operating conditions of the reinforced concrete structures.The bending of the beams leads to the development of cracks which are neither preceded nor accompanied by microcracks, but the cement paste-aggregate interfaces are damaged in the tensile areas.The service loading of reinforced concrete has two consequences : firstly, a cracking with widths ranging between 0.05 mm and 0.5 mm according to the intensity of the mechanical strength applied. Secondly, a damage of the ITZ in the tensile areas causing an increase of chloride penetration directly proportional to the intensity of the stress applied to the beam.The model of the development of corrosion, worked out in relation with time and based on our results, emphasizes the influence of the paste-aggregate interface damage on the duration of the service life.

scholarly journals About the influence of hardening conditions on the structure and properties of expansive concretes

2018 ◽  
Vol 193 ◽  
pp. 03025 ◽  
Author(s):  
Vyacheslav Alekseev ◽  
Igor Harchenko ◽  
Aleksey Harchenko ◽  
Sofia Bazhenova
Keyword(s):  
Research Methodology ◽  
Concrete Structures ◽  
Operating Conditions ◽  
Cement Stone ◽  
Structure And Properties ◽  
Technical Parameters ◽  
Material Change ◽  
Volumetric Deformation ◽  
Durability Of Concrete

The paper describes the effect of hardening conditions on the hydration of cement stone and methods of controlling the concrete formation on the basis of the above research methodology. It has been proved that when the humidity of the medium in which hardening takes place is regulated, the strength and the deformation of the material change. By adding an expand-ing component to concrete, it is possible to adjust the technical parameters of concrete and simulate the durability of concrete structures. Thus, the study of the mechanisms of volumetric deformation during hardening of cement stone with a different ratio of the expanding additive allows designing con-crete compositions for different operating conditions.

scholarly journals Improvement of Safety for the Underground Vertical Workings

2021 ◽  
pp. 41-48
Author(s):  
O.E. Khomenko ◽  
◽  
M.N. Kononenko ◽  
V.I. Lyashenko ◽  
◽  
...  
Keyword(s):  
Practical Experience ◽  
Operating Conditions ◽  
Theory And Practice ◽  
Mining Operations ◽  
New Device ◽  
Deep Wells ◽  
Solid Media ◽  
Tunneling Machine ◽  
Mine Workings ◽  
The Republic

The main scientific and practical calculations used to increase the efficiency of vertical mine workings based on studying the operation of tunneling complexes and road-heading machines, as well as by sectional blasting of the deep wells are presented in the article. This will ensure high-quality mine workings in accordance with the design and improve the operational safety throughout the entire service life. The methods are used related to the complex generalization, analysis and assessment of the practical experience and scientific achievements in the field of the underground geotechnology, theory and practice of explosive destruction of the solid media, mechanics of continuous media, mathematical statistics, as well as studies of the wave processes according to the standard and new methods developed by the leading experts from the leading mining countries of the world, including with the authors participation. Technological audit of the vertical working drilling and blasting was conducted using KPV-4A tunneling complex and the tunneling machine Robbins 73R, as well as the efficiency of conducting them in the cycle of mining operations was established. Mathematical modeling and calculation of the parameters of drilling and blasting operations were carried out using the contour blasting of explosive charges when driving vertical mine workings. Rounder of RS-220 type for the hole boring was recommended (complete with machine tool NKR-100MPА) of the downward wells with a diameter of 220 mm in rocks with a coefficient of f = 8–14 according to the scale of M.M. Protodyakonov, which is already being used at the mines of Ukraine, Russia, the Republic of Kazakhstan, and other countries. The new device for the contactless transmission of electricity from the stationary object to a mobile one was proposed, which will allow to improve the operating conditions of KPV-4A tunneling complex, LMSh-1 mine type elevator used for lifting and lowering people, small equipment, and materials along the rise workings, which is achieved due to external location of the cable rewinding mechanism and the absence of complex, for example, planetary mechanisms. It will also improve the efficiency and safety of work for the vertical mine workings in the rock massifs.

Mine Pressure and Rock Displacement Temporal Variation Analysis for Jiu Valley Directional Drifts in the Context of “n” Stability Criterion/Analiza Ciśnień I Chwilowych Przemieszczeń Skał W Badaniach Kierunkowych Wyrobisk W Kopalniach W Dolinie Jiu Z Uwzględnieniem Kryterium Stabilności ‘N’

2014 ◽  
Vol 59 (2) ◽  
pp. 455-466
Author(s):  
Mihaela Toderaş ◽  
Roland Iosif Moraru
Keyword(s):  
Stability Criterion ◽  
Operating Conditions ◽  
Mine Pressure ◽  
Coal Basin ◽  
Systems Research ◽  
Metal Type ◽  
Operation Period ◽  
Mine Workings ◽  
The Stability ◽  
Pressure Regime

Abstract Ensuring mine workings stability over their entire operation period largely depends on the chosen support system and on their interaction with the surrounding rock. Looking at how the main horizontal mine workings are supported in Jiu Valley coal basin, we found that they fall into the category fulfilling a reinforcement role. From the data provided by the documentation of the collieries within this basin, it was found that there were generalized different metal - type supporting systems that with respect to operating and working mode are with constant or malleable strength and increasing - strength (rigid supporting systems). Research conducted on the stability analysis of horizontal mine workings aimed at elucidate the intensiveness and characteristics of mine pressure, the deformation character and contour displacement of rocks, the interplay between geo-mechanical deformation conditions and deformation extension, as good as the influence of these parameters on the supporting system’s behavior. This paper presents a methodology for determining the main laws of mine pressure regime distribution, the results of the burden load values and displacement of support, considering the “n” stability criterion as a complex parameter which can express the laws of variation, for the specific location and operating conditions of directional galleries within the floor of coal seam 3 in Jiu Valley.

scholarly journals Thermal Performance of Alginate Concrete Reinforced with Basalt Fiber

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 779
Author(s):  
Seyed Esmaeil Mohammadyan-Yasouj ◽  
Hossein Abbastabar Ahangar ◽  
Narges Ahevani Oskoei ◽  
Hoofar Shokravi ◽  
Seyed Saeid Rahimian Koloor ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Thermal Performance ◽  
Concrete Structures ◽  
Basalt Fiber ◽  
Operating Conditions ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Structures ◽  
Anionic Polymer ◽  
Temperature Range

The sustainability of reinforced concrete structures is of high importance for practitioners and researchers, particularly in harsh environments and under extreme operating conditions. Buildings and tunnels are of the places that most of the fire cases take place. The use of fiber in concrete composite acts as crack arrestors to resist the development of cracks and enhance the performance of reinforced concrete structures subjected to elevated temperature. Basalt fiber is a low-carbon footprint green product obtained from the raw material of basalt which is created by the solidification of lava. It is a sustainable fiber choice for reinforcing concrete composite due to the less consumed energy in the production phase and not using chemical additives in their production. On the other hand, alginate is a natural anionic polymer acquired from cell walls of brown seaweed that can enhance the properties of composites due to its advantage as a hydrophilic gelling material. This paper investigates the thermal performance of alginate concrete reinforced with basalt fiber. For that purpose, an extensive literature review was carried out then two experimental phases for mix design and to investigate the compressive strength of samples at a temperature range of 100–180 °C were conducted. The results show that the addition of basalt fiber (BF) and/or alginate may slightly decrease the compressive strength compared to the control concrete under room temperature, but it leads to control decreasing compressive strength during exposure to a high temperature range of 100–180 °C. Moreover, it can be seen that temperature raise influences the rate of strength growth in alginate basalt fiber reinforced concrete.

scholarly journals Development of design solution for mine workings support repair and recovery in case of local massif deformations

2021 ◽  
Vol 315 ◽  
pp. 01010
Author(s):  
Sergey Tsibaev ◽  
Alexey Renev ◽  
Stepan Kalinin
Keyword(s):  
Rock Massif ◽  
Design Solution ◽  
Field Observations ◽  
Coal Rock ◽  
Mine Workings ◽  
Design Solutions ◽  
Term Field

The article describes the causes of occurrence and forms of geomechanical processes manifestation in surrounding coal-rock massif of mine workings supported by anchor support. Based on long-term field observations, six forms of typical deformations of the surrounding massif have been established. Design solutions to strengthen the anchor support or complete reinforcement of damaged sections of mine workings during geomechanical processes of local felling have been developed. They include: installation scheme, substantiation of parameters and list of used reinforcement elements; technology of work, a list of equipment used.

scholarly journals A Proposal of Rock Burst Control Measures at the Coalface No. 1 4064 at the Mining Plant 1, in OKD, A. S. Czech Republic

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Václav ZUBÍČEK ◽  
Vlastimil HUDEČEK ◽  
Milan KUBICA
Keyword(s):  
Czech Republic ◽  
High Risk ◽  
Rock Burst ◽  
Stress Level ◽  
Rock Massif ◽  
Control Measures ◽  
Rock Bursts ◽  
Mine Workings ◽  
Mining Plant

The paper describes a proposal of rock burst control measures for excavation and mining of the area the Coalface No. 1 4064, which is located in the 1st mining block of the Mining Plant 1, locality Karviná. It is an area that has been left in place as a protective area for safety reasons due to the high risk of rock bursts, and it is bordered on both sides by old workings.The aim of the proposal is to extract the retained area by using rock burst control measures to reduce this risk. As a measure, extensive disintegration of the rock massif in the overlying rocks of the seam by blasting works was chosen, both in driving mine workings and in mining of the coalface.The article describes the methods and scope of implementation of active and passive rock burst control measures in standard situations and in the case of detection of an unfavourable stress level.

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