scholarly journals NUMERICAL SIMULATION OF THE STABILITY OF THE SIDES OF COAL MINES UNDER THE INFLUENCE OF DISTRIBUTED LOADS

2020 ◽  
Vol 12 (3) ◽  
pp. 428-435
Author(s):  
Dashzhan NARODKHAN ◽  
◽  
Tuiak ISABEK ◽  
Rustam KHODJAEV ◽  
Nurbol KHUANGAN ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Critical Distance ◽  
Mining Operations ◽  
Bead Surface ◽  
Negative Effect ◽  
Strip Mine ◽  
The Republic ◽  
The Stability ◽  
Adjacent Rock

The open method of solid minerals winning occupies a significant place in the total opening of the mining complex deposits of the Republic of Kazakhstan. In the energy band, a prominent role belongs to the Ekibastuz coal basin, where a number of large coal strip mine operates. The level of subsurface, equal parts of spoil bank of the external and internal stripping after a while lead to complex problems of ensuring the stability and safety of mining operations. The location of large external rock dumps on the bead surface has a negative effect on the stability of the latter. The purpose of the work was to establish the degree of the external rock dump influence located on the bead surface on the stability of adjacent rock mass of the coalmine depending on the distance of the dump to the upper edge of the side. There was numerical simulation of stress-strain state of adjacent rock mass under action of distributed load from rock dump carried out. It has been shown that studies of any point stability of the array from this type of load should be carried out on the basis of elasticity and the use of the finite element method theory implemented in packages of programs oriented specifically to scientific and engineering applications. There are the methodology and results of numerical modeling of quantitative assessments of various sections stability of the side loaded with an external rock dump with a height of 160m presented on the example of «Ekibastuz» coal mine. Based on a certain theory of rock strength and the criteria for their discontinuity, limit estimates of the critical distance of the external rock dump from the upper edge of the side were obtained, at which the latter may lose stability.

Application of ABAQUS in Surrounding Rock Stability Analysis of Shallow Large Cross-Section Tunnel

2015 ◽  
Vol 777 ◽  
pp. 8-12 ◽  
Author(s):  
Lin Zhen Cai ◽  
Cheng Liang Zhang
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Strong Support ◽  
Surrounding Rock ◽  
Tunnel Engineering ◽  
Tunnel Excavation ◽  
Rock Stability ◽  
Rock Bolting ◽  
Excavation Support ◽  
The Stability

HuJiaDi tunnel construction of Dai Gong highway is troublesome, the surrounding-rock mass give priority to full to strong weathering basalt, surrounding rock integrity is poor, weak self-stability of surrounding rock, and tunnel is prone to collapse. In order to reduce disturbance, taking advantage of the ability of rock mass, excavation adopt the method of "more steps, short footage and strong support". The excavation method using three steps excavation, The excavation footage is about 1.2 ~ 1.5 m; The surrounding rock bolting system still produce a large deformation after completion of the first support construction, it shows that the adopted support intensity cannot guarantee the stability of the tunnel engineering. Using ABAQUS to simulate tunnel excavation support, optimizing the support parameters of the tunnel, conducting comparative analysis with Monitoring and Measuring and numerical simulation results, it shows that the displacement - time curves have a certain consistency in numerical simulation of ABAQUS and Monitoring and Measuring.

scholarly journals STABILITY ASSESSMENT OF ADJACENT ROCK MASS IN THE DEVELOPMENT OF COALBED OUTLETS

2018 ◽  
pp. 51-59
Author(s):  
Olga G. Bessimbaeva ◽  
Elena N. Khmyrova ◽  
Farit K. Nizametdinov ◽  
Elena A. Oleinikova
Keyword(s):  
Rock Mass ◽  
Coal Seam ◽  
Active Phase ◽  
Geological Structure ◽  
Stability Assessment ◽  
South Side ◽  
Southern Side ◽  
The Stability ◽  
External Forces ◽  
Adjacent Rock

The problems of stability assessment of the quarry’s southern side during the development of the coal seam D6 are considered. To  assess the stability of the quarry’s southern side in the development  of coalbed outlets, modern research methods are applied: study of  the geological structure and analysis of the adjacent rock mass  state, the creation of an observation station and the production of observations, calculation of stability of adjacent rock mass of the  quarry’s south side and the research results analysis. Quarry’s south  side consists of clayey sediments up to 5 m, then siltstones and  mudstones up to 10-20 m and a coal seam with a capacity of up to  5 m. The substantiation of the calculated strength characteristics of  rocks composing the slopes of the quarry ledges, which determine the stress state of the slopes arising under the influence  of internal and external forces, is done. Instrumental observations of the laid station and the survey of cracks on the quarry’s side allowed  to determine the contours of the deformation zone and the  landslide prism size. A geomechanical model of adjacent rock mass  was created and the stability assessment was carried out for the  geological section along the line of the maximum development  depth. After additional loading on the quarry’s southern side slopes,  the safety factor of stability is nу = 1.69−173, which means active  phase termination of quarry’s side deformation and sustainable condition.

scholarly journals Analysis of Possible Origination of Domes in Longwalls

2019 ◽  
Vol 4 (1) ◽  
pp. 57-64
Author(s):  
R. I. Imranov ◽  
E. N. Khmyrova ◽  
O. G. Besimbayeva ◽  
S. P. Olenyuk ◽  
A. Z. Kapasova
Keyword(s):  
Rock Mass ◽  
Factor Of Safety ◽  
Coal Seams ◽  
Mining Operations ◽  
Compressive Stresses ◽  
Digital Modeling ◽  
Geological Conditions ◽  
The Stability ◽  
High Ash Coal ◽  
Borehole Log

The research is aimed at solving problems of assessing underground working stability in complicated mining and geological conditions to increase reliability and safety of mining operations. Analysis of geomechanical processes occurring in a rock mass during extraction of coal seams to determine the stability of mining block roof is the most important task. The performed digital modeling of the rock mass based on the structural logs for K1 seam and the nearest borehole log enabled highly detailed identifying the types of rocks occurred in the seam roof and their strength characteristics, compressive stresses. To determine the stability of a mining block roof, the factor of safety of the rocks was used, which was determined by modeling method using Phase 28.0 and Rockscince software. The carbonaceous argillite parting 0.09–0.12 m thick was taken as the contact of the longwall with the seam roof, and, for completeness of the analysis, the upper high-ash coal member in the seam roof up to 0.7 m thick was used. The modeling findings, presented in the graph of dependence between the safety factor and the distance between the belt heading and air drift, showed that the probability of dome formation in the longwall is high, as the factor of safety of the rocks is less than unity, that indicates the roof instability in the course of the coal seam block extraction. The modeling methods allowed assessing the mine working stability, based on which the measures to improve the reliability and safety of mining operations can be timely developed, and due technical and technological solutions shall be reached.

scholarly journals Numerical Simulation of the Effect of Dynamic Stress on the Rock Surrounding a Mine Roadway

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Jun-hua Xue ◽  
Ke-liang Zhan ◽  
Xuan-hong Du ◽  
Qian Ma
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Rock Burst ◽  
Dynamic Stress ◽  
Simulation Method ◽  
Mining Areas ◽  
Geological Conditions ◽  
Mine Roadway ◽  
The Stability ◽  
Two Sides

In view of the damage of dynamic stress to the rock surrounding a mine roadway during coal mining, based on the actual geological conditions of Zhuji mine in Huainan, China, a UDEC model was established to study the influences of the thickness and strength of the direct roof above the coal seam and the anchorage effect on the stability of the roadway. The failure mechanism and effect of the dynamic stress on the rock surrounding a mine roadway were revealed. Under dynamic stress, cracks appear near the side of the roadway where the stress is concentrated. These cracks rapidly expand to the two sides of coal and rock mass. At the same time, the coal and rock mass at the top of the roadway fall, and finally, the two sides of coal and rock mass were broken and ejected into the roadway, causing a rock burst. However, when the same dynamic stress is applied to the roadway after supports are installed, there is no large-deformation failure in the roadway, which shows that, under certain conditions, rock bolting can improve the stability and seismic resistance of the surrounding coal and rock mass. Furthermore, by simulating the failure of surrounding rock with different strengths and thicknesses in the immediate roof, it is found that the thinner the roof, the greater the influence of the dynamic stress on the roadway; the stronger the roof is, the more likely the rock burst will occur with greater intensity under the same dynamic stress. A numerical simulation method was used to analyze the factors influencing rock bursting. The results provide a theoretical basis for research into the causes and prevention of rock bursts in deep mining areas.

scholarly journals Investigation of stress field parameters at deep horizons of the Gayskoye field**

2020 ◽  
Vol 192 ◽  
pp. 01028
Author(s):  
Sergey Sentyabov ◽  
Albert Zubkov
Keyword(s):  
Rock Mass ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Strength Properties ◽  
Concrete Lining ◽  
Complex Structures ◽  
Mining Operations ◽  
Volumetric Expansion ◽  
Shaft Lining ◽  
The Stability

The extraction of solid minerals is associated with the penetration of man into the subsoil by creating either relatively simple or extremely complex structures. All mining operations can be safely and efficiently carried out only on the basis of calculating the stability of these structures, which is based on knowledge of the physical and mechanical properties, the stress state of the rock mass and the patterns of their redistribution and formation in mountain structures. The presented studies confirmed the regularities of the formation of natural stresses in the rock mass, which is the sum of gravitational, static tectonic and variable components, which are formed as a result of uniform periodic volumetric expansion and contraction of the Earth. The problem of shaft stability is due to the need to solve problems to determine the level of stress-strain state and strength properties in concrete lining. The parameters of stresses in the shaft lining and monitoring of their changes were determined using the method of measuring unloading deformations. When analyzing the stresses obtained experimentally by analytical means in the concrete lining of mine shafts, a connection was established with the results of measurements in the rock mass on the basis of 50 meters. Based on the experiment, it was confirmed that theoretical and experimental studies prove that a hierarchically blocky massif of magmatic and metamorphic rocks behaves as an elastic and isotropic medium and changes in natural stresses in the massif Δ on the basis of 5-7 ranks of geoblocks, on the contour of the trunk based on 2 –3 ranks of geoblocks and in the concrete lining of mine shafts Δσb obey this law.

scholarly journals Study on the influence of the deformation zones of the quarry sides on the rock mass movement

2021 ◽  
Vol 304 ◽  
pp. 02002
Author(s):  
Vokhid Kadirov ◽  
Sherzod Karimov ◽  
Uchqun Qushshayev ◽  
Durdona Sharapova
Keyword(s):  
Rock Mass ◽  
Mass Movement ◽  
Physical And Mechanical Properties ◽  
Structural Features ◽  
Open Pit ◽  
Open Pit Mining ◽  
Rock Masses ◽  
Mining Operations ◽  
Dump Trucks ◽  
The Stability

The article presents a study and analysis of the causes of deformation of the slopes and sides of the quarry indicates that the magnitude and nature of the deformation processes depend on the height of the ledge, the angle of slope of the slopes, the physical and mechanical properties, the lithological and structural features of the instrument array and the geodynamic activity of the fault zones. The influence of the deformation zones of the sides of the quarry on the transport of rock masses is justified. The zone of deformed masses of the ore deposit, which affect the movement of the rock mass, is studied. Each process performed in open pit mining is linked to another workflow. Without ensuring the safety of mining operations and performing the tasks set is impossible. Transportation of rock masses in the lower horizons of a deep quarry is one of the main tasks of the industry. At the same time, the removal of deformation and landslides in the area where the transport berm is being constructed for draining and continuous transportation is the main goal of the quarry. The stability of the transport berm depends directly on the stability of the side of the quarry. It is determined that the choice of a single-lane or twolane transport berm constructed for heavy-duty quarry dump trucks depends on the condition of the side of the quarry.

scholarly journals Analysis of Stress-Strain States in the Vicinity of Mining Excavations in a Rock Mass with Variable Mechanical Properties

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5567
Author(s):  
Marek Jendryś ◽  
Stanisław Duży ◽  
Grzegorz Dyduch
Keyword(s):  
Mechanical Properties ◽  
Rock Mass ◽  
Numerical Simulations ◽  
Mechanical Parameters ◽  
Mining Operations ◽  
Axial Forces ◽  
Internal Forces ◽  
Random Variability ◽  
The Stability ◽  
The Impact

Rock mass is a medium created through processes that have lasted over four billion years, and its intrinsic feature is the variability of the parameters that describe it. A particularly high variability of mechanical parameters is observed in Carboniferous sedimentary and metamorphic rocks. The mechanical properties, especially the rock mass strength, are essential for the design and maintenance of the stability of excavations conducted in it and for the safe conduct of mining operations. This article presents the test results confirming the random variability of the mechanical parameters of the rock mass. The second part of the article presents the results of numerical simulations mapping the Carboniferous rock mass along with a 1000 m deep tunnel excavation protected by steel arch supports. Numerical simulations were carried out for models with different variability coefficients of strength and deformation parameters, and the obtained results were analyzed in terms of damage zones and rock mass stress state as well as axial forces in the modelled supports. The results of the simulation demonstrate the impact of the variability of rock mass properties on its state in the vicinity of the excavation and, consequently, on the internal forces in the steel supports and their uneven loading along the length of the excavation. This fact should be taken into account in their design.

A Constitutive Model of Anchored Jointed Rock Mass and its Application

2008 ◽  
Vol 33-37 ◽  
pp. 657-662
Author(s):  
Xiao Jing Li ◽  
Wei Min Yang ◽  
Wei Shen Zhu ◽  
Shu Cai Li ◽  
Ai Hua Sun
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Constitutive Model ◽  
Damage Mechanics ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
The Stability ◽  
Effective Reinforcement ◽  
Macroscopic Failure ◽  
Damage Equation

The jointed rock mass distributed in the nature widely and its mechanical characteristic influenced the stability of the rock engineering badly. The cracks propagated and coalesced each other and macroscopic failure happened. Bolts were a kind of effective reinforcement instrument and they could prevent the cracks from propagating. However, the anchoring mechanism of bolts was not realized clearly and their reinforcement could not be reflected effectively in the numerical simulation yet. Based on the damage mechanics, a constitutive relation and damage equation of anchored jointed rock mass were presented in this paper. With a project application, the model was proved to be feasible one.

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