The abutment pressure distribution of extremely thick seam top coal caving longwall panel

2014 ◽  
pp. 827-829 ◽  
Author(s):  
Hua Nan
Keyword(s):  
Pressure Distribution ◽  
Abutment Pressure ◽  
Thick Seam ◽  
Longwall Panel

scholarly journals A New Closed-Form Solution of the Side Abutment Pressure Distribution of Roadway

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Liang Cheng ◽  
Yidong Zhang
Keyword(s):  
Plastic Zone ◽  
Pressure Distribution ◽  
Closed Form ◽  
Abutment Pressure ◽  
Closed Form Solution ◽  
Evaluation Process ◽  
Friction Angle ◽  
Form Solution ◽  
Closed Form Solutions ◽  
Roadway Stability

Instability of coal wall is one of the hot-button and difficult issues in the study of coal mine ground control. The shallow side coal of roadway in the coal measures is usually weak and consequently easy to bring about failure. Hence, the side abutment pressure redistributes and dramatically influences the roadway stability. Since the previous closed-form solutions of the side abutment pressure do not take into account all the necessary parameters which include the properties of the coal and the interface between coal and roof/floor, the roadway height, and the support strength, a mechanical model is established based on the equilibrium of the plastic zone, and a new closed-form solution is derived in this paper. Moreover, a numerical investigation is conducted to validate the accuracy of the closed-form solution. The numerical results of the side abutment pressure distribution are in good agreement with the closed-form solution. Afterwards, a parametric analysis of the width of the plastic zone is carried out, and the results show that the width of the plastic zone is nearly negatively linearly correlated with the friction angle and the cohesion of the coal, the interfacial cohesion, and the support strength. By contrast, it is positively linearly correlated with the roadway height and negatively exponentially correlated with the interfacial friction angle. The results obtained in the present study could be useful for the evaluation process of roadway stability.

scholarly journals Abutment pressure distribution for longwall face mining through abandoned roadways

2019 ◽  
Vol 29 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Yang Li ◽  
Mingxing Lei ◽  
Haosen Wang ◽  
Cheng Li ◽  
Weiwei Li ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Abutment Pressure ◽  
Longwall Face

Finite Element Analysis of Abutment Pressure Distribution Characteristic of Working Faces in Fully Mechanized Sublevel Caving Face

2011 ◽  
Vol 71-78 ◽  
pp. 3358-3361 ◽  
Author(s):  
Hong Chun Xia ◽  
Zhen Qi Song ◽  
Li Jing Ru
Keyword(s):  
Finite Element Analysis ◽  
Abutment Pressure ◽  
Dynamic Change ◽  
Plastic Region ◽  
Constitutive Relationship ◽  
Distribution Characteristic ◽  
Element Analysis ◽  
Thick Seam ◽  
Sublevel Caving ◽  
Seam Mining

The elastic-plastic constitutive relationship and the Drucker-prager yielding criterion are used to simulate the behaviour of non-linear geo- materials. Dynamic change laws of abutment pressure of S2S2 work face of xiaokang coal mine is simuluted by the ansys program. It is shown that the distribution of abument pressure can be divided into two zones, elastic region and plastic region. The front inside the 13m distance is plastic zone. The zone outside 13m distance is elstic zone. The affecting scope is 144m when the concentrated coefficient of abutment pressure is 5%. The affecting scope is 160m when the concentrated coefficient of abutment pressure is 3%. The simulation provides a reference bases for the application and promotion of thick seam mining technology.

Study on Abutment Pressure Distribution Law of Fully-Mechanized Sublevel Caving Face in Extra-Thickness

2015 ◽  
Vol 1094 ◽  
pp. 405-409
Author(s):  
Lei Yu
Keyword(s):  
Pressure Distribution ◽  
Abutment Pressure ◽  
Distribution Law ◽  
Working Face ◽  
Sublevel Caving ◽  
Coal Wall ◽  
Pressure Peak ◽  
Cutting Height ◽  
Coal Seam Thickness ◽  
Peak Value

Based on field observation, analogy simulation and theoretical analysis, the abutment pressure distribution law of fully-mechanized sublevel caving face with extra-thickness was studied. The results showed that: Different instability type of the structure ‘Combined cantilever beam-articulated rock beam’ in fully-mechanized sublevel caving roof led to cyclical changes of abutment pressure; with an invariable coal seam thickness and increasing cutting height, abutment pressure peak value tended to stabilize after reaching the maximum, but as the working face advancing its location transferred to the front of coal wall working face and the influence region of abutment pressure increased; with an invariable cutting height and increasing once mining thickness, abutment pressure peak value decreased, and the distance between peak point and coal wall and the influence region increased. The results of the study would have some guiding role in extra-thickness fully mechanized mining’s safety and efficiency.

scholarly journals Influence of Upper Seam Extraction on Abutment Pressure Distribution during Lower Seam Extraction in Deep Mining

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Feng Wang ◽  
Zeqi Jie ◽  
Bo Ma ◽  
Weihao Zhu ◽  
Tong Chen
Keyword(s):  
Coal Seam ◽  
Pressure Distribution ◽  
Abutment Pressure ◽  
Field Measurements ◽  
Pressure Relief ◽  
Deep Mining ◽  
Key Strata ◽  
Mining Safety ◽  
Seam Mining ◽  
Overlying Strata

Pressure-relief coal mining provides an effective way to decrease stress concentration in deep mining and ensures mining safety. However, there is currently a lack of research and field verification on the pressure-relief efficiency and influencing factors during upper seam extraction on the lower seam. In order to make up for this deficiency, in this study, field measurements were conducted in panel Y485, which has a maximum depth of 1030 m and is partially under the goaf of the upper 5# seam in the Tangshan coal mine, China, and evolution of advanced abutment pressure was analyzed. Numerical simulations were conducted to study of influence of key strata on advanced abutment pressure. Influence mechanisms of the upper seam extraction on the advanced abutment pressure distribution during lower seam extraction were revealed. The results indicate that the distribution of advanced abutment stress is influenced by the key strata in the overlying strata. The key strata above the upper coal seam were fractured due to the upper coal seam mining, and the advanced abutment stress was only influenced by the key strata between the two seams during lower coal seam mining. When key strata were present between two seams, the extraction of the lower seam still faces potential dynamic disasters after the extraction of the upper seam. In this case, it would be necessary to fracture the key strata between the two seams in advance for the purpose of mining safety. Key strata in the overlying strata of the 5# seam were fractured during extraction, and advanced abutment pressure was only influenced by the key strata located between the two mined seams. The influence distance of advanced abutment pressure in panel Y485 decreased from 73 m to 38 m, and the distance between the peak advanced abutment pressure and the panel decreased from 29 m to 20.5 m, achieving a pronounced pressure-relief effect.

scholarly journals Research on Pressure Relief Hole Parameters Based on Abutment Pressure Distribution Pattern

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jian Hao ◽  
Hua Bian ◽  
Yongkui Shi ◽  
Anfa Chen ◽  
Jiankang Liu ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Distribution Pattern ◽  
Abutment Pressure ◽  
Coupling Effect ◽  
Large Diameter ◽  
Small Diameter ◽  
Surrounding Rock ◽  
Pressure Relief ◽  
Plastic Failure ◽  
Small Pore

Borehole pressure relief technology is an effective way to reduce the elastic energy in the surrounding rock of deep roadways, thereby reducing the risk of regional rock bursts. To avoid large deformation of the roadway caused by pressure relief holes with large diameters and insufficient pressure relief with small pore diameters, this study proposes precise pressure relief holes with nonequal diameters in order to achieve strong pressure relief with minimal disturbance based on the abutment pressure distribution pattern. To verify the pressure relief effect of the nonequal diameter holes, numerical simulations were performed in FLAC3D. This study investigated stress field, deformation laws, and plastic failure zone of roadway surrounding rock with 100 mm pressure relief holes, nonequal diameter precision pressure relief hole (100 mm + 300 mm), and 300 mm pressure relief holes. The simulation results show that, as the diameter of the pressure relief hole increases, the coupling effect of evenly spaced adjacent pressure relief holes is strengthened, thus improving the pressure relief efficiency. When pressure relief holes of nonequal diameter are adopted, the stress environment of the surrounding rock is clearly improved compared to100 mm pressure relief holes, and the plastic failure range increased by 2-3 times. The roof-to-floor convergence with nonequal diameter is 30.8% that of 300 mm pressure relief holes and 41% that of 100 mm pressure relief holes. Furthermore, the rib displacement is 30.4% and 46.9% that of 300 mm and 100 mm pressure relief holes, respectively. Thus, precise pressure relief holes with nonequal diameter provide both strong pressure relief associated with large diameter holes and small disturbance of small diameter of small holes. This study provides a reference for precise pressure relief application with pressure relief holes.

scholarly journals Method to Calculate Working Surface Abutment Pressure Based on Key Strata Theory

2019 ◽  
Vol 2019 ◽  
pp. 1-20 ◽  
Author(s):  
Hongkai Han ◽  
Jialin Xu ◽  
Xiaozhen Wang ◽  
Jianlin Xie ◽  
Yantuan Xing
Keyword(s):  
Pressure Distribution ◽  
Elastic Foundation ◽  
Abutment Pressure ◽  
Coal Pillar ◽  
Beam Theory ◽  
Coal Mass ◽  
Fissure Zone ◽  
Key Strata ◽  
Working Surface ◽  
Subsidence Zone

Overburden key strata (KS) have a significant influence on abutment pressure distribution. However, current calculation methods for working surface abutment pressure do not consider the influence of the overburden KS. This study uses KS theory to analyze the overburden load transferred to coal-rock masses on both sides of the stope through fractured blocks in different layers of the KS in the fissure zone and KS in different layers of the curve subsidence zone. Using Winkler’s elastic foundation beam theory, we consider the fissure zone KS on the coal mass side and the curve subsidence zone KS as many elastic foundation beams interact with each other. A method to calculate the abutment pressure of the coal mass and the goaf was then established, considering the influence of the overburden KS. The abutment pressure distribution of working surface 207 after mining was then calculated using our method, based on mining conditions present in the Tingnan coal mine. The calculated results were verified using measurements from borehole stress meters and microseismic monitoring systems, as well as numerical simulations. In addition, the calculation results were used to determine a reasonable position for the stopping line and remaining width of the roadway’s protection coal pillar in working surface 207. The results of this study can be used to calculate the abutment pressure distribution of the working surface under a variety of overburden KS conditions. The results can also provide guidance for forecasting and preventing mine dynamic hazards, controlling the surrounding rock in mining roadways, determining reasonable widths for protection coal pillars, and designing the layout of mining roadways.

scholarly journals Coal Mine Abutment Pressure Distribution Based on a Strain-Softening Model

2020 ◽  
Vol 8 ◽  
Author(s):  
Ang Li ◽  
Qiang Ma ◽  
Li Ma ◽  
Li Kang ◽  
Qian Mu ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Coal Mine ◽  
Abutment Pressure ◽  
Strain Softening
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