Modeling of the stress-state longwall face during coal mining with the technology of roof management complete drop and stowing

2020 ◽  
pp. 99-106
Author(s):  
I. E. Mazina ◽  
A. A. Stel’makhov ◽  
L. F. Mullagalieva
Keyword(s):  
Coal Mining ◽  
Strain State ◽  
Underground Mining ◽  
Negative Impact ◽  
Hydrological Regime ◽  
Coal Bed ◽  
Stress Strain ◽  
Environmental Friendliness ◽  
Modeling And Analysis ◽  
Stress Strain State

Underground mining of coal deposits has a negative impact on all components of the environment. When developing a coal deposit, it is coal mining technology that determines the scale and consequences of the negative impact. Changes in the stress-strain state of the geo-environment can lead to a violation of the hydrological regime, increased gas emission from the host rocks, the initiation of gas-dynamic processes. Choice of roofing management technology - as a geotechnological method of natural and technical system management determines the environmental friendliness of coal mining and creates safety conditions. The article deals with the technology of roofing control during coal production. For this purpose mathematical modeling and analysis of stress-strain state of the bottomhole part of the coal bed for the conditions of S.M. Kirov is performed. As a result of modeling, two technologies of roof control were analyzed - complete caving and stowing. For the worked out clearing leaves filled with either caving rocks or stowing material, there are characteristic unloading zones in the massif to be worked and overworked, as well as pressure reference zones, which fall on the parts of the pillars associated with the lava. It was found out that the application of the stowing technology creates conditions for minimization of gravitational stresses in the geoenvironment, as well as significantly reduces the potential energy of form change.

scholarly journals MODELING AND ANALYSIS OF THE DEFORMED MEDIA (METAL CONSTRUCTION ELEMENTS) NON STATIONARY THERMAL FIELDS DURING THEIR LASER SHORT WAVES PULSES TREATMENT

2021 ◽  
pp. 277-296
Author(s):  
Yuriy Chovnyuk ◽  
Petro Cherednichenko ◽  
Volodymyr Kravchyuk ◽  
Olga Ostapushchenko ◽  
Eugenie Ivanov
Keyword(s):  
Strain State ◽  
Fourier Method ◽  
Laser Pulses ◽  
Porous Films ◽  
Stress Strain ◽  
Modeling And Analysis ◽  
Thermal Fields ◽  
Short Waves ◽  
Stress Strain State ◽  
Metal Construction

Substantiated mathematical model for non-stationary thermoelastic deformed media during their laser processing by short waves pulses fields analysis is proposed . Precise analytical solutions of the thermal conductivity equations  which simulate the short laser pulses interaction and allow to further determine their components thermally stress-strain state of the processed materials, in particular, thin porous films, capillary-porous bodies are obtained. Two analysis methods were used: 1) traditional separating variables method (Fourier method), 2) non-Fourier analysis of the non-stationary thermal fields that described by the telegraphic equation known in the literature. The results obtained in this work can be used further to establish the thermo stress-strain state of materials interacting with short waves laser radiation pulses parameters. Such approach is used at the modern building process for the rising of the reliability, durability and strength of the metal construction elements.

scholarly journals STUDY OF THE INFLUENCE OF PARAMETERS TECHNOLOGICAL SCHEMES OF EXCAVATION ON THE SUSTAINABILITY OF MINE ROADWAYS WHEN IMPLEMENTING THE CONCEPT OF «SMALL MINES»

2020 ◽  
pp. 64-73
Author(s):  
Svitlana Sakhno ◽  
◽  
Victoria Borodich ◽  
Yevhen Karlov
Keyword(s):  
Coal Mining ◽  
Strain State ◽  
Point Of View ◽  
Practical Significance ◽  
Stress Strain ◽  
Stress Strain State ◽  
Rock Stability ◽  
Complex Mechanization ◽  
Mine Roadways ◽  
First Time

Purpose. Investigation of the influence of the parameters of technological schemes of coal mining on the stress-strain state of the rocks containing the mine roadways in the implementation of the concept of «small mines». Methods. The study used the finite element method and the analysis method. Modeling was carried out by the method of dangerous sections. According to the first variant of the technological scheme, two dangerous sections were selected, according to the second – four. The solution of the problem was carried out in a volumetric setting with observance of the boundary conditions. Results. The analysis of the stress-strain state of the rocks around mine roadways, according to the compared options, made it possible to determine the expected state of the rocks and establish the parameters of the zones of possible destruction. From the point of view of rock stability at the stage of elastoplastic deformation of rocks, the compared options are almost equivalent. Taking into account the shorter time of maintenance of roadways, it is more expedient to use short longwalls. In this version, trapezoidal support is used as the main fastening in the roadways, and in the “traditional” version – metal arch support. It is shown that with significantly lower costs for maintaining mine roadways, their stability when using short-longwall technological schemes is better. The studies carried out make it possible to assert that for “small mines” with small production, technological schemes with short longwalls are more appropriate than the “traditional” technological schemes developed for complex mechanization. Scientific novelty. The study of the stress-strain state of rocks around mine roadways of various shapes and sizes during the analysis of technological schemes for coal mining with short longwalls made it possible to establish the orientation and parameters of the massif sections that pass into an out-of-bounds state. This was done for the first time for the conditions of the Ukrainian Donbass. Practical significance. The availability of information about the expected stress-strain state of the rock mass allows timely planning of methods of fastening and measures to increase the local stability of rocks. Keywords: stresses, deformations, development, coal mine, technological schemes of excavation.

scholarly journals Registration of the Emission of Submicron Particles of Rocks to Predict the Destruction of Underground Mine Workings at Rockburst-Hazardous Deposits

2019 ◽  
pp. 50-62
Author(s):  
S.D. Viktorov ◽  
A.A. Osokin ◽  
A.V. Shlyapin ◽  
I.N. Lapikov
Keyword(s):  
Rock Pressure ◽  
Strain State ◽  
Underground Mining ◽  
Submicron Particles ◽  
Structural Defects ◽  
Anthropogenic Activity ◽  
Stress Strain ◽  
Rock Formation ◽  
Stress Strain State ◽  
Rock Formations

The results of studies of the conditions for the formation of submicron particles from the surface of the rock formation under the influence of external factors are presented. The deformation and destruction of the mass of rock formations under the conditions of anthropogenic activity under the influence of rock pressure and blasting are characterized by the origin and development of structural defects at various scale levels. A method for recording the emission of submicron particles is proposed to carry out experimental work forstudies of the process of disintegration and the formation of free particles. The results of laboratory studies of the stress-strain state of rock formation samples with a through cylindrical cavity under uniaxial compression, made on the basis of a physical model for the formation of submicron particles from the surface of the samples under study, are presented. The sizes and nature of changes in stress concentration zones and fracture under quasi-static uniaxial loading of specimens are determined. The loading limits have been established to ensure the transfer of rock formation samples to the pre-fracture state. The obtained results are necessary for the development of a fundamentally new method and hardware-technical base for recording dynamic forms of manifestation of rock pressure and prediction of rockbursts in the conduct of underground mining. The results of experimental-industrial tests of the method for determining the stress-strain state of a specific section of a rock formation massif based on the phenomenon of submicron particle emission are presented.

scholarly journals Effect of increasing mining rate on longwall coal mining – Western donbass case study

2016 ◽  
Vol 38 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Olena Sdvyzhkova ◽  
Renata Patyńska
Keyword(s):  
Coal Mining ◽  
Strain State ◽  
Rapid Change ◽  
Rock Stress ◽  
Strength Theory ◽  
Mining Operations ◽  
Stress Strain ◽  
Statistical Strength ◽  
Roof Collapse ◽  
Stress Strain State

Abstract This paper presents the problems associated with the rapid change of the rock stress-strain state in terms of increasing the rate of coal mining. Parameters of the roof collapse are determined depending on the rate of a longwall advancing under conditions of poor rocks. Statistical data are processed to obtain a general trend concerning the mining rate impact on the roof collapse. The statistical strength theory is applied to explain the increase in mined-out space and the size of hanging roof behind a coal face. Numerical simulation is carried out to determine a critical size of mined-out space that provokes a roof collapse. The area of yielded rocks is outlined using the criterion developed taking into account the rate of longwall advancing. A general regularity is obtained to determine the roof collapse parameters. The developed technics gives a possibility to predict the moment of general roof collapse at the initial stage of longwalling to prevent the negative effect of the rapid stress redistribution provoking joints propagation and intensive gas release. The estimation of the rock stress-strain state considering the rate of mining operations can be useful for tasks related to a new technology implementation. The statistical strength theory and failure criterion applied together provides adequate planning of mining activities and the assessment of natural hazards.

scholarly journals Protective Measures during Construction of Ground Structures over Existing Underground Structures

2020 ◽  
Vol 19 (5) ◽  
pp. 377-383
Author(s):  
A. A. Dalidovskaya ◽  
V. G. Pastushkov
Keyword(s):  
Strain State ◽  
Negative Impact ◽  
Surface Structures ◽  
Underground Structures ◽  
Safe Operation ◽  
Stress Strain ◽  
Protective Measures ◽  
Stress Strain State ◽  
New Construction ◽  
The Impact

Today, there is an acute issue of ensuring the safe operation of buildings and structures located in the immediate vicinity of new construction. The process of performing works on the installation of load-bearing structures and their further operation can have a negative impact on already existing facilities. In this regard, the task of developing innovative methods and tools to ensure the safe operation of such structures as subway running tunnels is very urgent. To solve it, a reliable forecast of additional deformation and appointment of a complex of protective measures are required.  In addition, much attention should be paid to the numerical modeling of the system “surface structures – protective measures – underground structures”. As an example of assessing the impact of new construction, namely, the erection of surface structures over existing underground  ones, one  can  cite  the  construction  of  a transport  interchange  at  the  intersection  of  Nezavisimosty  Avenue with Filimonov Street. As protective measures, a protective screen on bored piles has been used here, which made it possible to minimize significantly dynamic and static effects on the lining of tunnels and other underground structures of the subway. Effectiveness of protection application is confirmed by the result of monitoring the stress-strain state of running tunnel structures at all stages of traffic  intersection construction. Protective measures and continuous monitoring of the stress-strain state in structures help to avoid accidents during construction and further operation. 

Sign in / Sign up

Export Citation Format

Share Document