Analysis of geodynamic behavior of rock mass for the purpose of rock burst prediction

Author(s):  
B.R. Raimjanov ◽  
A.R. Khasanov ◽  
O.E. Farmanov
2018 ◽  
Vol 22 ◽  
pp. 5-9
Author(s):  
Krishna Kanta Panthi

Tunnels and underground caverns located at greater depth (high rock cover or overburden) are subjected to high in-situ stress environment. Those rock mass that are relatively unjointed and massive are exposed to the brittle failure, which is famously known as rock spalling/ rock bursting phenomenon. Establishing state of the stress and evaluating stress-induced instability in tunnels passing through such rock mass at relatively greater depth is therefore a challenge. The aim of this manuscript is to describes existing brittle failure (rock burst) prediction methods that are being practiced worldwide and propose necessary editions so that quality of assessment is enhanced. The methods described are very practical and the author is confident that professional engineers will use them to evaluate and predict potential rock burst/ rock spalling scenario in the tunnels during planning, design and construction phases. Each method of prediction is explained, applicability extent is highlighted and comparisons between the methods are made.  HYDRO Nepal JournalJournal of Water Energy and EnvironmentIssue No: 22Page: 5-9Uploaded date: January 14, 2018


Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 562
Author(s):  
Marek Jendryś ◽  
Andrzej Hadam ◽  
Mateusz Ćwiękała

The following article analyzes the effectiveness of directional hydraulic fracturing (DHF) as a method of rock burst prevention, used in black coal mining with a longwall system. In order to define changes in seismic activity due to DHF at the “Rydułtowy” Black Coal Mine (Upper Silesia, Poland), observations were made regarding the seismic activity of the rock mass during coal mining with a longwall system using roof layers collapse. The seismic activity was recorded in the area of the longwall itself, where, on a part of the runway, the rock mass was expanded before the face of the wall by interrupting the continuity of the rock layers using DHF. The following article presents measurements in the form of the number and the shock energy in the area of the observed longwall, which took place before and after the use of DHF. The second part of the article unveils the results of numerical modeling using the discrete element method, allowing to track the formation of goafs for the variant that does not take DHF into consideration, as well as with modeled fractures tracing DHF carried out in accordance with the technology used at “Rydułtowy” coal mine.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Shuai Di

Deep rock burst accidents occur frequently and become increasingly serious. Further improving the effectiveness and accuracy of the prevention and control of rock burst, ensuring the safe and efficient production of mines, clarifying the basic causes of disasters, and refining the type of deep rock burst are the most important key links. Aiming at the problems such as unclear incentives and types and the lack of effective and targeted prevention measures of deep rock burst, taking Xin’an Mine as the research background, based on the energy theory, the coal and rock mass multisource energy unified equation was established to analyze coal and rock mass instability mechanism. According to the different degrees of participation of various factors, the types of deep rock burst are determined as three categories and four types, and the corresponding judgment criteria are proposed. The precise prevention and control system for the source of rock burst with Xin’an characteristics is proposed, successfully applied to the 8101 working face, which not only guarantees the safe production of the working face, but also achieves good economic benefits. The research results lay the foundation for improving the accuracy and precision of the prevention and control of deep rock burst and provide theoretical guidance for the safe and efficient mining of the mine.


2011 ◽  
Vol 243-249 ◽  
pp. 2885-2888
Author(s):  
Xian Min Han ◽  
Shou Ding Li

Experiments of unloading confining pressure of rock were conducted to reveal deformation characteristics of rock mass under different excavation intension in thigh geostress condition. It were concluded from tests that volumetric strain of rock is inverse proportional to unloading rate. The smaller the unloading rate, the bigger the ductility of rock. Energy release are bigger under high unloading rate than that under low unloading rate. That means that tendency of rock burst turn smaller when unloading rates decrease.


Author(s):  
Lipin Iakov ◽  
◽  
Sentiabov Sergei ◽  
Krinitsyn Roman ◽  
◽  
...  

Research aim is to study parameter variations in the stress state of the rock mass to ensure safe and efficient mining of the Peschanskoye magnetite deposit (Northern Ural) to the full depth, which has been carried out by Severopeschanskaya mine since 1958 in a complex of hard rock at a depth of 200 to 700 m. Blind, thick, and steep ore bodies are developed by a block-caving method with ore breaking to a clamped medium. From a depth of 400 m, the field is classified as rock burst hazardous. The first rock burst was recorded in 1981 at a depth of 450 m. Research methodology includes full-scale experimental measurements of the rock and ore mass stress state at accessible depths and horizons of the deposit, establishing patterns of stress growth with depth, as well as long-term (since 1990) geo-deformational monitoring of an untouched rock mass stress level in time. Research results analysis has allowed to establish the patterns in stress-strain state changes during mining. Gradients of gravitational and tectonic stresses growth with depth are determined. Alternating (astrophysical) stresses are highlighted in a special line, the extreme values of which are linked chronologically with various information factors. Conclusions. The determined values of rock mass natural stress state variation parameters in combination with the established stresses around the workings and goafs (technogenic impact) make it possible to take into account the main tempo-spatial factors of the impact made by the mentioned loads when selecting rockburst-safe and effective mining parameters for underground geotechnology both at the top horizons when applying controlled collapse of overlying blind deposits and in the prevention of rockburst hazard in the lower horizons of the developed field


2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Jun-hua Xue ◽  
Ke-liang Zhan ◽  
Xuan-hong Du ◽  
Qian Ma

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.


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