scholarly journals The Study on Large-Diameter Drilling Prevention Method of Rock Burst in the Xinxing Coal

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Gao Xu ◽  
Zuo Minghui ◽  
Shu Yanmin
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Plastic Zone ◽  
Rock Burst ◽  
Large Diameter ◽  
Practical Implementation ◽  
Physical Parameters ◽  
Mine Pressure ◽  
Working Face ◽  
Geological Conditions

Based on the engineering background, the 41051 working face of the 65th coal mine in Qitaihe Xinxing Mine was regarded as the engineering background, by using of the comprehensive research methods such as theoretical analysis and calculation, FLAC3D numerical simulation, physical parameters of coal and rock in laboratory, and the field industrial measurement, to research on the large drilling relieving rock burst mechanism and parameter setting in reasonable. The distribution of stress and plastic zone in drilling surrounding rock and its influence parameters are clarified, and the distribution of the “butterfly plastic zone” and the mutation condition of the “butterfly plastic zone” in trigger stress state are explored. On the basis, combined with theoretical analysis and numerical simulation, studying the rock burst prevention and treatment mechanism in large drilling, through the statistics of the Xinxing mine pressure characteristics, the measurement of the physical parameters of coal and rock and the test of ground stress finding is that the coal satisfies “Three hard” condition in Xinxing mine and is affected by larger horizontal tectonic stress. Combined with the real geological conditions, the layout parameters of relief pressure large drilling are simulated, and the result shows that the drilling of 600 diameters and 10 m pitch of hole and throughout the working face is reasonable, and the effect is obvious about pressure relief. For the practical implementation, the electromagnetic radiation monitoring is used to evaluate the effect in field; to comprehensive analysis, the relief pressure large drilling has obvious control effect to the 41051 workface rock burst.

Numerical Simulation on the Stress Distribution of Thin Seam Containing Iron-Sulfide-Cores

2013 ◽  
Vol 316-317 ◽  
pp. 799-802 ◽  
Author(s):  
Yun Liang Tan ◽  
Wei Min Li ◽  
Su Jun Miao ◽  
Ping Wei ◽  
Tong Bin Zhao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Plastic Zone ◽  
Iron Sulfide ◽  
Mining Area ◽  
Three Dimensions ◽  
Mine Pressure ◽  
Lagrangian Analysis ◽  
Working Face ◽  
Stress Curve ◽  
Thin Seam

Fast Lagrangian Analysis of Continua in three Dimensions was adapted to establish numerical model of thin seam with Iron-sulfide-cores, based on the conditions of thin seam in Yanzhou Mining Area, and the influence of existing cores or not, cores in different positions, cores contents on mine pressure was studied. The results showed that, stress concentration and plastic zone is more easily to be formed in the coal around cores. When there are cores in coal, the bahaviors of abutment stress foreside the working face have no significant differences, the abutment stress curve is fluctuation and width or range of plastic zone little changed, but the boundary of plastic zone is fuzzy and radial. The boundary of plastic zone has some difference with the increasing of cores contents, but other macroscopic mine pressure behaviors has no significant differences. It is helpful to understand spalling mechanism of iron-sulfide-cores in thin seam.

scholarly journals Study on Microseismic Monitoring, Early Warning, and Comprehensive Prevention of a Rock Burst under Complex Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Ke Ding ◽  
Lianguo Wang ◽  
Mei Yu ◽  
Wenmiao Wang ◽  
Bo Ren
Keyword(s):  
Coal Seam ◽  
Rock Burst ◽  
Large Diameter ◽  
Elastic Strain Energy ◽  
Surrounding Rock ◽  
Control Effect ◽  
Pressure Relief ◽  
Working Face ◽  
Geological Conditions ◽  
Microseismic Events

Rock bursts in coal mines are usually unpredictable. In view of this problem, the energy–frequency relationship and spatial distribution characteristics of microseismic events during the mining of 5305 working face in Xinhe Coal Mine under complex geological conditions were analyzed in this study. Besides, the law and precursors of rock burst occurrence in this working face were discussed. The following research results were obtained. Before the rock burst occurred in 5305 working face, the energy and frequency of microseismic events vary in the following order: “peak-drop-rise-rock burst.” The analysis on spatial characteristics of microseismic events suggests that microseismic events were mainly concentrated at the boundary between the roof and the coal seam or at the hard roof near the coal seam within 0–160 m in front of the working face, and most of the events lay on the goaf side. Moreover, the energy and frequency of microseismic events both decrease in the above region before the rock burst occurred. This “microseismic event absence” phenomenon can be regarded as one of the precursors of rock burst occurrence. In addition, a multilevel antiburst scheme was proposed for the complex conditions: (1) to adopt large-diameter boreholes pressure relief technology and key layer high-level pressure relief technology for adjusting the stress distribution in the surrounding rock of crossheading in front of the working face and dissipating elastic strain energy; (2) to determine the advance speed to be 1.5 m/d for reducing the mining disturbance; (3) to adopt full-section reinforced support of the roadway for enhancing the antiburst capacity of surrounding rock. After the implementation of this scheme, the energy and frequency of microseismic events monitored on-site changed gently, and 5305 working face was safely recovered to the stop line position. The scheme boasts a remarkable rock burst prevention and control effect.

scholarly journals The design of bottomhole assembly with two rock cutting tools for directional drilling

2018 ◽  
pp. 14-20
Author(s):  
I. V. Voievidko ◽  
V. V. Tokaruk ◽  
M. A. Bodzian
Keyword(s):  
Theoretical Analysis ◽  
Inclination Angle ◽  
Large Diameter ◽  
Cutting Tools ◽  
Intensity Variation ◽  
Rock Cutting ◽  
Hole Drilling ◽  
Directional Drilling ◽  
Geological Conditions ◽  
Technical Factors

On the basis of the theoretical analysis and practical studies of hole drilling of large diameter, a method for designing the BHA with two rock cutting tools is proposed, taking into account the geological and technical factors that have an impact on the formation of the trajectory. The calculation of BHA with two rock cutting tools and a different number of supporting and centralizing components for different geological conditions of drilling is carried out and the analysis of their work in the process of drilling is conducted. The graphic dependences of the deviation intensity variation and the inclination angle with the sinking of borehole of the large diameter for the BHA that can be used for the drilling of vertical and directional wells.

scholarly journals Evolution Laws of Mining-induced Stress in Floor Strata and Its Influence on the Stability of a Floor Roadway Affected by Overhead Mining

2020 ◽  
Vol 24 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Pu Wang ◽  
Lishuai Jiang ◽  
Changqing Ma ◽  
Anying Yuan
Keyword(s):  
Numerical Simulation ◽  
Mechanical Model ◽  
Scientific Basis ◽  
Pull Out ◽  
Induced Stress ◽  
Working Face ◽  
Geological Conditions ◽  
Evolution Laws ◽  
The Stability

The study of evolution laws of the mining-induced stress in floor strata affected by overhead mining is extremely important with respect to the stability and support of a floor roadway. Based on the geological conditions of the drainage roadway in the 10th district in a coalmine, a mechanical model of a working face for overhead mining over the roadway is established, and the laws influencing mining stress on the roadway in different layers are obtained. The evolution of mining stress in floor with different horizontal distances between the working face and the floor roadway that is defined as LD are examined by utilizing UDEC numerical simulation, and the stability of roadway is analyzed. The results of the numerical simulation are verified via on-site tests of the deformation of the surrounding rocks and bolts pull-out from the drainage roadway. The results indicate that the mining stress in floor is high, which decreases slowly within a depth of less than 40 m where the floor roadway is significantly affected. The mining stress in the floor increases gradually, and the effect of the mining on the roadway is particularly evident within 0 m ≤ LD ≤ 40 m. Although the floor roadway is in a stress-relaxed state, the worst stability of the surrounding rocks is observed during the range -20 m ≤ LD < 0 m, in which the negative value indicates that the working face has passed the roadway. The roadway is affected by the recovery of the abutment stress in the goaf when -60 m ≤ LD <20 m, and thus it is important to focus on the strengthening support. The results may provide a scientific basis for establishing a reasonable location and support of roadways under similar conditions.

scholarly journals Deviatoric Stress Evolution Laws and Control in Surrounding Rock of Soft Coal and Soft Roof Roadway under Intense Mining Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Dongdong Chen ◽  
Chunwei Ji ◽  
Shengrong Xie ◽  
En Wang ◽  
Fulian He ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Plastic Zone ◽  
Theoretical Calculations ◽  
Coal Pillar ◽  
Surrounding Rock ◽  
Deviatoric Stress ◽  
Anchor Cable ◽  
Soft Coal ◽  
Working Face ◽  
Failure Line

Aiming at the problem of large deformation and instability failure and its control of soft coal and soft roof roadway under intense mining, laboratory experiments, theoretical calculations, Flac3D numerical simulation, borehole peeping, and pressure observation were used to study the deflection characteristics of the deviatoric stress of the gas tailgate and the distribution and failure characteristics of the plastic zone in the mining face considering the strain softening characteristics of the roof and coal of roadway, and then the truss anchor cable-control technology is proposed. The results show the following: (1) The intense mining influence on the working face will deflect the peak deviatoric stress zone (PDSZ) of the surrounding rock of the gas tailgate. The influence distance of PDSZ is about 20 m in advance and 60 m in lag; the PDSZ at the gob side of the roadway is located in the range of 3–5.5 m from the surface of the coal pillar, while the coal wall side is mainly located in the range of 3–4.5 m at the shoulder corner and bottom corner of the solid coal. (2) The intense mining in the working face caused the nonuniform expansion of the surrounding rock plastic area of the gas tailgate. The two shoulder angles of the roadway and the bottom of the coal pillar have the largest damage range, and the maximum damage location is the side angle of the coal pillar (5 m). Angle and bottom angle of coal pillar are the key points of support control. (3) The plastic failure line of the surrounding rock of the gas tailgate is always between the inner and outer contours of the PDSZ, and the rock mass in the PDSZ is in a stable and unstable transition state, so the range of anchor cable support should be cross plastic failure line. (4) The theoretical calculations and numerical simulation results agree well with the drilling peep results. Based on the deflection law of the PDSZ and the expansion characteristics of the plastic zone, a truss anchor cable supporting system with integrated locking and large-scale support function is proposed to jointly control the roof and the two sides, which effectively solves the problem of weak surrounding rock roadway under severe mining deformation control problems realizing safety and efficient production in coal mines under intense mining.

scholarly journals Control of Gob-Side Roadway with Large Mining Height in Inclined Thick Coal Seam: A Case Study

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xie Fuxing
Keyword(s):  
Numerical Simulation ◽  
Coal Pillar ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Mine Pressure ◽  
Thick Coal Seam ◽  
Working Face ◽  
Rock Structure ◽  
Large Mining Height ◽  
Mining Height

The gob-side roadway of 130205, a large-mining-height working face in the Yangchangwan coal mine, was investigated in terms of the mine pressure law and support technology for large mining heights and narrow coal pillars for mining roadways. The research included field investigations, theoretical analysis, numerical simulation, field tests, and other methods. This paper analyzes the form of movement for overlying rock structure in a gob-side entry with a large mining height and summarizes the stress state and deformation failure characteristics of the surrounding rock. The failure mechanism of the surrounding rock of the gob-side roadway and controllable engineering factors causing deformation were analyzed. FLAC3D numerical simulation software was used to explore the influence law of coal pillar width, working face mining height, and mining intensity on the stability of the surrounding rock of the gob-side roadway. Ensuring the integrity of the coal pillar, improving the coordination of the system, and using asymmetric support structures as the core support concept are proposed. A reasonably designed support scheme for the gob-side roadway of the working face for 130205 was conducted, and a desirable engineering effect was obtained through field practice verification.

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 A Control Method of Rock Burst for Dynamic Roadway Floor in Deep Mining Mine

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Zhimin Xiao ◽  
Jun Liu ◽  
Shitan Gu ◽  
Mingqing Liu ◽  
Futian Zhao ◽  
...  
Keyword(s):  
Rock Burst ◽  
Control Method ◽  
Tectonic Stress ◽  
Surrounding Rock ◽  
Floor Rock ◽  
Deep Mining ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Working Face ◽  
Geological Conditions

Roadway floor rock burst is an important manifestation of rock bursts in deeply buried mines. With the increase of mining depth and mining intensity, rock burst disasters in the roadway floor such as floor heaves are becoming more serious. The article investigated the roadway floor severe heave caused by floor rock burst during excavation of the No. 3401 working face, which was controlled by an anticlinal structure and deep mining in Shandong Mine, China. Firstly, by analyzing geological conditions of the working face, roadway support parameters, and characteristics of coal and rock, it was revealed that high tectonic stress and high crustal stress were main causes of the floor rock burst. Secondly, based on the Theory of Mechanics and Theory of Energy, the energy conversion process in the roadway floor was discussed, and the rock burst condition caused by elastic energy in the roadway floor was analyzed. The failure characteristics of roadway-surrounding rock were also inspected, using a borehole recorder. The roof and sidewalls of roadway mainly contained fissures and cracks, whereas cracks and broken areas are distributed in the roadway floor. Finally, based on the deformation and failure characteristics of roadway-surrounding rock, a method termed “overbreaking-bolting and grouting-backfill” was proposed to control roadway floor rock burst. The method was tested in the field, and the results showed that it could effectively control the deformation of roadway floor and rock burst, guaranteeing the stability of roadway floor. This impact control method for the roadway floor can provide a reference for the prevention and control of roadway rock burst in mines with similar geological conditions.

Study on Pressure Regularity of the Fully Mechanized Coal Mining Face and Evaluation on Support Adaptability

2013 ◽  
Vol 734-737 ◽  
pp. 838-842
Author(s):  
Xing Shun Wang
Keyword(s):  
Theoretical Analysis ◽  
Coal Mining ◽  
Rock Pressure ◽  
Field Testing ◽  
Mine Pressure ◽  
Pressure Monitoring ◽  
Technical Parameters ◽  
Analysis And Evaluation ◽  
Working Face ◽  
Mining Face

Based on the theoretical analysis and field testing, for making clear of the roofs strata behaviors characteristics in the fully mechanized coal mining face in Hongliulin coal mine, and evaluating the adaptability of the support to the roof movement of the working face, this paper gives a collection analysis and evaluation of the rock pressure information during the working faces extraction to get the related technical parameters that can reflect the roof activity rule and the support adaptability analysis and meanwhile to provide some references for the mine pressure monitoring under the similar conditions.

scholarly journals Theoretical Analysis and Numerical Simulation of the Graben Fault Instability Mechanism

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Qihua Ma ◽  
Shiwei Niu ◽  
Huaguo Wang ◽  
Weixiang Ma ◽  
Lihui Chi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Rock Burst ◽  
Recovery Process ◽  
Instability Mechanism ◽  
Geological Structures ◽  
Ground Pressure ◽  
Working Face ◽  
Shear Beam ◽  
Rock Strata ◽  
Elastic Shear

The rock burst caused by geological structures is abrupt and destructive, and the special structure of a graben fault decides the uniqueness of mine ground pressure in the mining process. By simplifying the graben fault structure, the evolution law of roof stress during the recovery process was studied based on the theory of the elastic shear beam. The change laws of stress field and displacement nearby the fault during the advancement process of the working face were explored through a numerical simulation, and the instability mechanism and laws of rock strata nearby this graben fault were revealed. This study will be of great significance for preventing and controlling the rock burst in the graben fault.

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