The Numerical Simulation of Overburden Strata Failure Law by Full-Mechanized Caving Mining in Extra Thick Coal Seams

2014 ◽  
Vol 962-965 ◽  
pp. 1179-1182 ◽  
Author(s):  
Shao Jie Feng ◽  
Xue Fang Zhao ◽  
Shi Guo Sun
Keyword(s):  
Numerical Simulation ◽  
Mining Area ◽  
Fracture Zones ◽  
Thick Coal Seam ◽  
Thick Seam ◽  
Fractured Zone ◽  
Working Face ◽  
Geological Conditions ◽  
Close Proximity ◽  
Superposition Effect

Given the irrationality and limitations in thick coal seam of the empirical formula of height of water flowing fractured zone , this article reveals the special thick seam fully mechanized mining damaging rules of overlying rock and determines the height of water flowing fractured zone with 3D finite element numerical simulation,according to the complex geological conditions and the special thick seam fully mechanized mining methods of Laohutai ore mining working face E5400 as an example. Results show that the destruction of repeated mining area of the overlying rock will have superposition effect and the superposition effect will increase with the development of mining; the fracture sharp of water fracture zones is in close proximity to the "arch". Simulation results and the actual detection height fitting is better, so it assesses the range of overburden water flowing fracture zones and rationality of the height.

scholarly journals Disastrous Mechanism of Water Discharge in Abandoned Gob above the Stope in Mining Extra-Thick Coal Seam

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Haixiao Lin ◽  
Feng Yang ◽  
Zhengzheng Cao ◽  
Yue Wang ◽  
Xiaojian Jiao
Keyword(s):  
Coal Seam ◽  
Water Discharge ◽  
Mining Area ◽  
Thick Coal Seam ◽  
Research Results ◽  
Key Stratum ◽  
Working Face ◽  
Geological Conditions ◽  
Induced Fractures ◽  
Seam Mining

The Datong mining area is a typical double system coal seam mining area in China, where the Jurassic and Carboniferous coal seams are mined simultaneously. The upper Jurassic coal seam has been largely mined, leaving a large amount of gob area. Besides, a large amount of harmful water is accumulated. With the exploitation of the 3-5# extra-thick coal seam in the Carboniferous system, the scope of overburden damage is greatly increasing, and the mining fracture field is further developed. Once the mining-induced fractures connect with the overlying gob, it is easy to induce the water discharge disaster. With the mining geological conditions of the 8202 working face in the Tongxin coal mine as references, the disastrous mechanism of water discharge in the abandoned gob above the stope in the mining extra-thick coal seam is researched by numerical simulation with the UDEC numerical software, and the research results are obtained. The water in the overlying gob percolates through the mining-induced fractures in the higher key layer forming a “shower” seepage pattern. The water in the above gob converges in the key fracture channel, flowing into the working face. The seepage in the fractures in the high key stratum experiences the process of increase, decrease, and stabilization, related with the stretching and extrusion deformation between the high key stratum blocks. Compared with other fractures, the flow rates in the No.2 and No.4 fractures in the far field key lay are larger, because the fractures are in the tension state, forming the “saddle-shaped” flow pattern. The influencing distance of mining-induced seepage is about 80 m in front of the working face. The research results provide a guided reference for the prediction and prevention of water discharge disaster in an abandoned gob above the stope in a mining extra-thick coal seam.

scholarly journals A numerical simulation of realistic top coal caving intervals under different top coal thicknesses in longwall top coal caving working face

2021 ◽  
Author(s):  
Chuang Liu ◽  
Huamin Li
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Distinct Element ◽  
Simulation Models ◽  
Simulation Software ◽  
Thick Coal Seam ◽  
Coal Recovery ◽  
Working Face ◽  
Longwall Top Coal Caving ◽  
Selection Of

Abstract In the process of longwall top coal caving, the selection of the top coal caving interval along the advancing direction of the working face has an important effect on the top coal recovery. To explore a realistic top coal caving interval of the longwall top coal caving working face, longwall top coal caving panel 8202 in the Tongxin Coal Mine is used as an example, and 30 numerical simulation models are established by using Continuum-based Distinct Element Method (CDEM) simulation software to study the top coal recovery with 4.0 m, 8.0 m, 12.0 m, 16.0 m, 20.0 m and 24.0 m top coal thicknesses and 0.8 m, 1.0 m, 1.2 m, 1.6 m and 2.4 m top coal caving intervals. The results show that with an increase in the top coal caving interval, the single top coal caving amount increases. The top coal recovery is the highest with a 0.8 m top coal caving interval when the thickness of the top coal is less than 4.0 m, and it is the highest with a 1.2 m top coal caving interval when the coal seam thickness is greater than 4.0 m. These results provide a reference for the selection of a realistic top coal caving interval in thick coal seam caving mining.

scholarly journals A Mechanical Model of the Overlying Rock Masses in Undersea Coal Mining and a Stress-Seepage Coupling Numerical Simulation

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Jie Fang ◽  
Lei Tian ◽  
Yanyan Cai ◽  
Zhiguo Cao ◽  
Jinhao Wen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Coal Mining ◽  
Water Inrush ◽  
Mining Area ◽  
Analysis Model ◽  
Fractured Zones ◽  
Working Face ◽  
Seam Mining ◽  
Overlying Strata

The water inrush of a working face is the main hidden danger to the safe mining of underwater coal seams. It is known that the development of water-flowing fractured zones in overlying strata is the basic path which causes water inrushes in working faces. In the engineering background of the underwater mining in the Longkou Mining Area, the analysis model and judgment method of crack propagation were created on the basis of the Mohr–Coulomb criterion. Fish language was used to couple the extension model into the FLAC3d software, in order to simulate the mining process of the underwater coal seam, as well as to analyze the initiation evolutionary characteristics and seepage laws of the fractured zones in the overlying strata during the advancing processes of the working face. The results showed that, during the coal seam mining process, the mining fractured zones which had been caused by the compression-shear and tension-shear were mainly concentrated in the overlying strata of the working face. Also, the open-off cut and mining working face were the key sections of the water inrush in the rock mass. The condition of the water disaster was the formation of a water inrush channel. The possible water inrush channels in underwater coal mining are mainly composed of water-flowing fractured zones which are formed during the excavation processes. The numerical simulation results were validated through the practical engineering of field observations on the height of water-flowing fractured zone, which displayed a favorable adaptability.

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.

Numerical Simulation Research of Optimization Design of Supporting Half-Coal Roadway in Deep Stope Working Face

2014 ◽  
Vol 945-949 ◽  
pp. 1169-1174
Author(s):  
Xian Tao Zeng ◽  
Ning Wang ◽  
Cong Jiang ◽  
Yun Yi Zhang ◽  
Chang Hai He
Keyword(s):  
Numerical Simulation ◽  
Optimization Design ◽  
Mining Area ◽  
Support Design ◽  
Simulation Research ◽  
Actual Measurement ◽  
Design Scheme ◽  
Coal Roadway ◽  
Working Face ◽  
Ground Stress

In this paper, design of roadway with stope working face Yeqing 8459 had been optimized combined with geological characteristics of the working face based on the actual measurement of ground stress and mechanical properties of coal rock of Yangquhe mine in Feng Feng mining area. Analyzing eight kinds of roadway support design scheme through numerical simulation and evaluating the supporting effect of each supporting design scheme, designating the construction guidelines ultimately.

scholarly journals Determination of cyclic filling length in gob-side entry retained with roadside filling and its application

2020 ◽  
Author(s):  
Zizheng Zhang ◽  
Jianbiao Bai ◽  
Xianyang Yu ◽  
Weijian Yu ◽  
Min Deng ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Difference Method ◽  
Suggested Method ◽  
Stress Difference ◽  
Thick Coal Seam ◽  
Mechanics Model ◽  
Working Face ◽  
Geological Conditions ◽  
The Relationship

Abstract Gob-side entry retained with roadside filling (GER-RF) plays a key role in achieving coal mining without pillar and improving the coal resource recovery rate. Since there are few reports on the cyclic filling length of GER-RF, a method based on the stress difference method is proposed to determine the cyclic filling length of GER-RF. Firstly, a stability analysis mechanics model of the immediate roof above roadside filling area in GER was established, then the relationship between the roof stress distribution and the unsupported roof length was obtained by the stress difference method. According to the roof stability above roadside filling area based on the relationship between the roof stress and its tensile strength, the maximum unsupported roof length and rational cyclic filling length of GER-RF. Combined with the geological conditions of the 1103 thin coal seam working face of Heilong Coal Mine and the geological conditions of the 1301 thick coal seam working face of Licun Coal Mine, this suggested method was applied to determine that the rational cyclic filling lengths of GER-RF were 2.4 m and 3.2 m, respectively. Field trial tests show that the suggested method can effectively control the surrounding rock deformation along with rational road-in support and roadside support, and improve the filling and construction speed.

scholarly journals The Research on Stability of Surrounding Rock in Gob-side Entry Driving in Deep and Thick Seam

2021 ◽  
Author(s):  
jianjun SHI ◽  
Feng Jicheng ◽  
Peng Rui ◽  
Zhu Quanjie
Keyword(s):  
Stability Study ◽  
Surrounding Rock ◽  
Support Pressure ◽  
Thick Coal Seam ◽  
Thick Seam ◽  
Working Face ◽  
Pressure Area ◽  
Roadway Support ◽  
The Stability ◽  
Bolt Steel

Abstract The gob-side entry driving is driving in low pressure area, which bears less support pressure and is easy to maintain, so it is widely used. Taking the gob-side entry driving in thick coal seam of Dongtan Coal Mine as an example, the reasonable size of pillar and the section of roadway are numerically simulated by combining numerical with measurement, and the roadway support is designed. According to the distribution of lateral stress in working face, eight pillars of different sizes are designed. By simulating and comparing the stress distribution of surrounding rock and the development range and shape of plastic zone in different positions, the pillar size of gob-side entry driving is optimized to be 4.5m. According to the results of optimization of roadway section, the section of straight wall semi-circular arch roadway is adopted. According to the analysis, the roadway is supported by bolt + steel mesh + anchor cable. By observing the stability of roadway, it provides experience for the stability study of roadway the gob-side entry driving with small pillar in thick seam.

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.

The Influence of Mining Height on the Height of Water Flowing Fractured Zone

2012 ◽  
Vol 524-527 ◽  
pp. 481-484
Author(s):  
Ming Zhang ◽  
Jian Guo Ning
Keyword(s):  
Numerical Simulation ◽  
Protective Layer ◽  
Theoretical Formula ◽  
Maximum Height ◽  
Similar Material ◽  
Minimum Thickness ◽  
Fractured Zone ◽  
Working Face ◽  
Coal Pillars ◽  
Mining Height

Under the background of the hydrogeology conditions of the first working face of 11 coal seam in LuXin coal mine, theoretical formula prediction and numerical simulation were used to research the influence of mining height on the growth altitude of water flowing fractured zone. According to the requirement of the minimum thickness of waterproof coal pillars, the reasonable mining height was confirmed to be 3m. It was proved by similar material simulation that the maximum height of water flowing fractured zone was about 39.5m when the mining height is 3m, which was consistent with results of numerical simulation, and the thickness of protective layer was 23.5m, which ensured the safety of mining.

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