Study on the Abutment Pressure and Advanced Support of Driving Roadway along Goaf of Isolated Mining Face

2014 ◽  
Vol 941-944 ◽  
pp. 2533-2538
Author(s):  
Li Li ◽  
An Bin Zhang ◽  
Chun Lei Zhang
Keyword(s):  
Numerical Simulation ◽  
Stress Concentration ◽  
Abutment Pressure ◽  
Simulation Software ◽  
Study Results ◽  
Safety Production ◽  
Advanced Support ◽  
Mining Face ◽  
Roadway Deformation ◽  
Peak Value

WuTongZhuang No.182309 mining face is an isolated mining face. The abutment pressure is big and roadway deformation is severe due to driving roadway along goaf with short pillar remained. In view of these problems, taking WuTongZhuang No.182309 mining face as project background, the law of the abutment stress distribution was analyzed by use of numerical simulation software FLAC3D and field measurement study. The results showed that the influence scope of the lead abutment pressure was about 55m , the peak value was about 6m ahead of the mining face and the stress concentration factor is 3.3.Based on the above study results, a scheme of advanced support was proposed which effectively controlled the roadway deformation and ensured the safety production of the mining face.

scholarly journals The Influences of Key Strata Compound Breakage on the Overlying Strata Movement and Strata Pressure Behavior in Fully Mechanized Caving Mining of Shallow and Extremely Thick Seams: A Case Study

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Junmeng Li ◽  
Yanli Huang ◽  
Jixiong Zhang ◽  
Meng Li ◽  
Ming Qiao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Abutment Pressure ◽  
Simulation Software ◽  
Strata Movement ◽  
Key Strata ◽  
Pressure Behavior ◽  
Ground Pressure ◽  
Working Face ◽  
Overlying Strata Movement ◽  
Overlying Strata

In order to analyze the impact of compound breakage of key strata on overlying strata movement and strata pressure behavior during the fully mechanized caving mining in shallow and extremely thick seams, this paper took the 1322 fully mechanized caving face in Jindi Coal Mine in Xing County as the engineering background. Under the special mining and geological condition mentioned above, UDEC numerical simulation software was applied to research the engineering problems, and results of numerical simulation were verified through the in-site measurement. The research results showed that during the fully mechanized caving mining in shallow and extremely thick seams, the inferior key strata affected by mining movement behaved in the mode of sliding instability and could not form the stable structure of the voussoir beam after breaking and caving. In addition, the main key strata behaved in the mode of rotary instability, and the caving rocks behind the goaf were gradually compacted because of the periodic instability of the main key strata. With the continuous advance of the working face, the abutment pressure of the working face was affected by the compound breakage and periodic instability of both the inferior key strata and the main key strata, and the peaks of the abutment pressure presented small-big-small-big periodical change characteristics. Meanwhile, the risk of rib spalling ahead of the working face presented different levels of acute or slowing trends. The actual measurement results of ground pressure in the working face showed that, in the working process, the first weighting interval of the inferior key strata was about 51 m and its average periodic weighting interval was about 12.6 m, both of which were basically consistent with the results of numerical simulation. The research has great significance in providing theoretical guidance and practical experience for predicting and controlling the ground pressure under the similar mining and geological conditions.

scholarly journals Numerical Investigation of Gob-Side Entry Retaining through Precut Overhanging Hard Roof to Control Rockburst

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Xiaoming Sun ◽  
Li Gan ◽  
Zhao Chengwei ◽  
Tang Jianquan ◽  
He Manchao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Abutment Pressure ◽  
Feasibility Studies ◽  
Main Roof ◽  
Surrounding Rock ◽  
Distribution Characteristics ◽  
Hard Roof ◽  
Working Face ◽  
Stress Fluctuation ◽  
Peak Value

Gob-side entry retaining through precut overhanging hard roof (GERPOHR) method is one of the commonly used methods for nonpillar mining. However, feasibility studies of controlling rockburst by this method are few. Rockburst occurs in hard thick strata with a higher probability, larger scale, and higher risk. To better understand the GERPOHR method is beneficial for rockburst mitigation. In this paper, the design of GERPOHR was first introduced. And the layout of the working face was optimized. Then, based on the numerical simulation, the stress and displacement distribution characteristics were compared under the condition of conventional mining and GERPOHR method. The research shows that the intervals of main roof weighting could be decreased through the precut overhanging hard roof method. And the peak value of abutment pressure decreased. Meanwhile, the energy accumulation and the stress fluctuation could be alleviated in roadway surrounding rock.

Study on Energy and Stress of Irregular Failure Zone of Upper Layered in Slice Mining

2013 ◽  
Vol 734-737 ◽  
pp. 828-832
Author(s):  
Xiao Biao Zhang ◽  
Kun Zhou ◽  
Hai Tao Li ◽  
Jiao Xia Liu ◽  
Yun Yi Zhang
Keyword(s):  
Numerical Simulation ◽  
Stress Concentration ◽  
Coal Pillar ◽  
Simulation Software ◽  
Failure Zone ◽  
Surrounding Environment ◽  
Production Safety ◽  
Residual Coal ◽  
Delamination Area ◽  
Slice Mining

Under the condition of the top layered have irregular zone , due to the stress concentration caused by the upper leaf residual coal pillar , lower leaf will increase recovery difficult. This article reappear the scene of irregular top delamination area and the surrounding environment by FLAC3D numerical simulation software, receive the distribution condition of stress, displacement and the elastic energy of media under this condition, provide abundant basis for develop highly targeted production safety measuresa, solve the problem of data range is smaller,because the restriction of the detection equipment and other technical reasons detection equipment under the scene.

The Numerical Study of the Stability of Roadway Seeping in the Roof

2012 ◽  
Vol 178-181 ◽  
pp. 1293-1296
Author(s):  
Feng Zhen Liu ◽  
Wei Guo Qiao
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Plastic Zone ◽  
Numerical Study ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Key Factors ◽  
Roadway Stability ◽  
The Stability ◽  
Roadway Deformation

Seepage in the roof is one of main reasons resulting softening rock and roadway deformation, in order to make sure about the influence of seepage on the roadway stability, we established corresponding models by using numerical simulation software, and analyzed the stress distribution, the deformation of surrounding rock, and the distribution range and shape of the plastic zone, the results show that water is one of the key factors to influence the stability of roadway, seepage makes the strength of surrounding rock sharply reduce, and the roof, two ribs and floor appear serious deformation.

The Applied Research of Loose Blasting Technique in Managing Crushing Accident of Fully Mechanized Coal Mining Face

2013 ◽  
Vol 734-737 ◽  
pp. 863-867 ◽  
Author(s):  
Jian Wen Wang
Keyword(s):  
Rock Mass ◽  
Theoretical Basis ◽  
Applied Research ◽  
Abutment Pressure ◽  
Surrounding Rock ◽  
Load Test ◽  
Hydraulic Support ◽  
Dynamic Load Test ◽  
Safety Production ◽  
Mining Face

Support crushing accidents occur frequently in coal mines, which have a serious impact on their safety production. Usually people adopt the loose blasting technology for processing the pressing frame accidents, that is, using the detonative action generated by explosives to cause the rock mass particles vibration which would spread in the form of stress wave to crush the surrounding rock mass. After the release of the rock mass internal stress, the hydraulic support would make use of its own abutment pressure to prop up again the overlying rock and make it work normally. Based on the research of detonative action and making use of FLAC3D numerical simulation technology, this paper provides a theoretical basis as well as the experience for handling the pressing frame accidents by applying a dynamic load test to theoretically calculate the appropriate explosive amount.

Study on Reasonable Filling Width of Gob-Side Entry Retaining and its Engineering Application

2013 ◽  
Vol 807-809 ◽  
pp. 2288-2293 ◽  
Author(s):  
Xiang Qian Wang ◽  
Xiang Rui Meng ◽  
Zhao Ning Gao
Keyword(s):  
Numerical Simulation ◽  
Coal Mining ◽  
Coal Mine ◽  
Field Measurement ◽  
Engineering Application ◽  
Coal Pillar ◽  
Simulation Software ◽  
Mining Face ◽  
Pillar Size

Based upon the engineering background of IV315 coal mining face of Mengzhuang Coal Mine, the numerical simulation software UDEC is used to analyze rational packing width under the conditions of different filling widths on the driving roadway. The rational coal pillar size is initially decided as 2.0 meters through simulating and analyzing. On this basis, the influence of second mining on the retaining roadway was analyzed by numerical simulation. Combined with the field measurement, the support parameters and the 2.0 meters packing width are proven to be rational, which provides a reference for the coal mining faces with similar conditions.

scholarly journals Numerical and Experimental Study of Lightning Stroke to BIPV Modules

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 748
Author(s):  
Xiaoyan Bian ◽  
Yao Zhang ◽  
Qibin Zhou ◽  
Ting Cao ◽  
Bengang Wei
Keyword(s):  
Numerical Simulation ◽  
Experimental Study ◽  
Coupling Model ◽  
Maximum Temperature ◽  
Lightning Stroke ◽  
Study Results ◽  
Pv Modules ◽  
New Type ◽  
Metal Frame ◽  
Current Flows

Building Integrated Photovoltaic (BIPV) modules are a new type of photovoltaic (PV) modules that are widely used in distributed PV stations on the roof of buildings for power generation. Due to the high installation location, BIPV modules suffer from lightning hazard greatly. In order to evaluate the risk of lightning stroke and consequent damage to BIPV modules, the studies on the lightning attachment characteristics and the lightning energy withstand capability are conducted, respectively, based on numerical and experimental methods in this paper. In the study of lightning attachment characteristics, the numerical simulation results show that it is easier for the charges to concentrate on the upper edge of the BIPV metal frame. Therefore, the electric field strength at the upper edge is enhanced to emit upward leaders and attract the lightning downward leaders. The conclusion is verified through the long-gap discharge experiment in a high voltage lab. From the experimental study of multi-discharge in the lab, it is found that the lightning interception efficiency of the BIPV module is improved by 114% compared with the traditional PV modules. In the study of lightning energy withstand capability, a thermoelectric coupling model is established. With this model, the potential, current and temperature can be calculated in the multi-physical field numerical simulation. The results show that the maximum temperature of the metal frame increases by 16.07 °C when 100 kA lightning current flows through it and does not bring any damage to the PV modules. The numerical results have a good consistency with the experimental study results obtained from the 100 kA impulse current experiment in the lab.

scholarly journals Design of Customize Interbody Fusion Cages of Ti64ELI with Gradient Porosity by Selective Laser Melting Process

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 307
Author(s):  
Cheng-Tang Pan ◽  
Che-Hsin Lin ◽  
Ya-Kang Huang ◽  
Jason S. C. Jang ◽  
Hsuan-Kai Lin ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Selective Laser Melting ◽  
Stress Shielding ◽  
Simulation Software ◽  
Surrounding Tissue ◽  
Shielding Effect ◽  
Stress And Strain ◽  
Laser Melting ◽  
Flexion Extension ◽  
Intervertebral Cage

Intervertebral fusion surgery for spinal trauma, degeneration, and deformity correction is a major vertebral reconstruction operation. For most cages, the stiffness of the cage is high enough to cause stress concentration, leading to a stress shielding effect between the vertebral bones and the cages. The stress shielding effect affects the outcome after the reconstruction surgery, easily causing damage and leading to a higher risk of reoperation. A porous structure for the spinal fusion cage can effectively reduce the stiffness to obtain more comparative strength for the surrounding tissue. In this study, an intervertebral cage with a porous gradation structure was designed for Ti64ELI alloy powders bonded by the selective laser melting (SLM) process. The medical imaging software InVesalius and 3D surface reconstruction software Geomagic Studio 12 (Raindrop Geomagic Inc., Morrisville, NC, USA) were utilized to establish the vertebra model, and ANSYS Workbench 16 (Ansys Inc, Canonsburg, PA, USA) simulation software was used to simulate the stress and strain of the motions including vertical body-weighted compression, flexion, extension, lateral bending, and rotation. The intervertebral cage with a hollow cylinder had porosity values of 80–70–60–70–80% (from center to both top side and bottom side) and had porosity values of 60–70–80 (from outside to inside). In addition, according to the contact areas between the vertebras and cages, the shape of the cages can be custom-designed. The cages underwent fatigue tests by following ASTM F2077-17. Then, mechanical property simulations of the cages were conducted for a comparison with the commercially available cages from three companies: Zimmer (Zimmer Biomet Holdings, Inc., Warsaw, IN, USA), Ulrich (Germany), and B. Braun (Germany). The results show that the stress and strain distribution of the cages are consistent with the ones of human bone, and show a uniform stress distribution, which can reduce stress concentration.

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