scholarly journals Plastic zone range of a roadway considering the creep effect

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Haidong Chen ◽  
Xiangjun Chen ◽  
Zhaofeng Wang ◽  
Zhiqiang Li ◽  
Fenghua An
Keyword(s):  
Plastic Zone ◽  
Pressure Measurement ◽  
Field Experiments ◽  
Coal Mines ◽  
Calculation Model ◽  
Gas Pressure ◽  
Gas Drainage ◽  
Research Results ◽  
Damage Characteristics ◽  
Creep Effect

AbstractThe plastic zone range is an important parameter in the analysis of damage characteristics and the degree of damage to the rock surrounding a roadway. Based on the establishment of a plastic zone calculation model considering the creep effect, this paper obtains the characteristics of the change in the plastic zone damage range with time by solving the model. Additionally, the validity of the model is verified by field experiments. The research results can provide guidance for gas pressure measurement and gas drainage in coal mines.

scholarly journals Nano silica diaphragm in-fiber cavity for gas pressure measurement

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Shen Liu ◽  
Yiping Wang ◽  
Changrui Liao ◽  
Ying Wang ◽  
Jun He ◽  
...  
Keyword(s):  
Pressure Measurement ◽  
Gas Pressure ◽  
Nano Silica

scholarly journals Permeability Enhancement Properties of High-Pressure Abrasive Water Jet Flushing and Its Application in a Soft Coal Seam

2021 ◽  
Vol 9 ◽  
Author(s):  
Xinzhe Zhang ◽  
Piotr Wiśniewski ◽  
Sławomir Dykas ◽  
Guojie Zhang
Keyword(s):  
High Pressure ◽  
Coal Seam ◽  
Water Jet ◽  
Gas Pressure ◽  
Theory And Practice ◽  
Abrasive Water Jet ◽  
Gas Drainage ◽  
Permeability Enhancement ◽  
Soft Coal ◽  
Soft Coal Seam

High-pressure abrasive water jet flushing (HPAWJF) is an effective method used to improve coal seam permeability. In this study, based on the theories of gas flow and coal deformation, a coupled gas-rock model is established to investigate realistic failure processes by introducing equations for the evolution of mesoscopic element damage along with coal mass deformation. Numerical simulation of the failure and pressure relief processes is carried out under different coal seam permeability and flushing length conditions. Distributions of the seepage and gas pressure fields of the realistic failure process are analyzed. The effects of flushing permeability enhancement in a soft coal seam on the gas drainage from boreholes are revealed by conducting a field experiment. Conclusions can be extracted that the gas pressure of the slotted soft coal seam is reduced and that the gas drainage volume is three times higher than that of a conventional borehole. Field tests demonstrate that the gas drainage effect of the soft coal seam is significantly improved and that tunneling speed is nearly doubled. The results obtained from this study can provide guidance to gas drainage in soft coal seams regarding the theory and practice application of the HPAWJF method.

A Mathematical Calculation Method for Hysteresis Characteristics Analysis of Arc-Shaped Finger Seal

2020 ◽  
Author(s):  
Chun-Hua Du ◽  
Yan-Chao Zhang ◽  
Ya-Hui Cui ◽  
Shu-Na Dong ◽  
Hong-Hu Ji ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Structural Parameters ◽  
Maximum Error ◽  
Calculation Model ◽  
Correction Coefficient ◽  
Research Results ◽  
Characteristics Analysis ◽  
Leakage Characteristics ◽  
The Mathematical Model ◽  
Hysteresis Characteristics

Abstract In order to accurately predict the hysteresis characteristics of finger seal, the minimum hysteresis which can directly reflect the hysteresis of finger seal is proposed to characterize the hysteresis of finger seal. The mathematical model for calculating the minimum hysteresis of finger seal is established, the correction coefficient in the mathematical model is determined, and the mathematical model is verified by experiments. The influence of the structure and working condition parameters of finger laminates on the hysteresis characteristics is studied based on the modified calculation model, and the rule of influence is obtained in the end. Research results show that the maximum error between the leakage characteristics numerical calculation of finger seal base on modified calculation model and the experiment results is 7.64%, and the mathematical model of the minimum hysteresis is reasonable and reliable. The descending order of influence degree of structural parameters on the hysteresis characteristics of finger seal is: thickness of each finger laminate, finger repeat angle, arc radius of the finger beam arcs‘ centers, diameter of the finger base circle, width of the interstice between fingers, arc radius of finger beam. The research results provide a theoretical basis for further research on the influence of hysteresis on the finger seal leakage characteristics and the optimal design of finger seal structure.

Gas-pressure measurement for preparing ICF cryotargets

2012 ◽  
Vol 24 (10) ◽  
pp. 2343-2346
Author(s):  
林伟 Lin Wei ◽  
王凯 Wang Kai ◽  
毕鹏 Bi Peng ◽  
黎军 Li Jun ◽  
马坤全 Ma Kunquan ◽  
...  
Keyword(s):  
Pressure Measurement ◽  
Gas Pressure

scholarly journals Failure Mechanism of a Coal-Rock Combined Body with Inclinations of Structural Planes and a Calculation Model for Impact Energy

2019 ◽  
Vol 2019 ◽  
pp. 1-18
Author(s):  
Yi-Chao Zhao ◽  
Ming-Shi Gao ◽  
Yong-Liang He ◽  
Dong Xu
Keyword(s):  
Mechanical Properties ◽  
Failure Mechanism ◽  
Impact Energy ◽  
Coal Mines ◽  
Calculation Model ◽  
Engineering Practice ◽  
Test Results ◽  
Failure Characteristics ◽  
Coal Rock ◽  
Rock Strata

A coal-rock (CR) combined body can be used to simulate structures of coal and rock strata, and its impact-induced failure characteristic conforms more close to engineering practice. Exploring the mechanical properties and impact energy in a CR combined body contributes to better predictions of rock bursts in coal mines. In the study, the mechanical properties of CR combined bodies with four different inclinations (0°, 15°, 30°, and 45°) of structural planes were measured, and also their failure mechanism was analysed. Based on the theory of particle mechanics, a calculation model for impact energy in a CR combined body with inclinations was established and then verified by using monitored acoustic emission (AE) data. The test results showed that inclination affected mechanical properties and failure characteristics of the CR combined body, i.e., the larger the inclination, the lower the strength and impact energy in the CR combined body and the lower the level of damage. The proposed calculation model for impact energy revealed the mechanical essence of energy accumulation and release of a CR combined body, providing a reference for investigating rock burst in coal mines.

scholarly journals Experimental Investigation on Mechanics and Seepage Characteristics of Tectonic and Intact Coal Containing Gas

2020 ◽  
Vol 10 (20) ◽  
pp. 7290
Author(s):  
Chaolin Zhang ◽  
Enyuan Wang ◽  
Jiang Xu ◽  
Shoujian Peng
Keyword(s):  
Coalbed Methane ◽  
Triaxial Compression ◽  
Coal Mines ◽  
Gas Pressure ◽  
Extraction Time ◽  
Gas Extraction ◽  
Effective Measure ◽  
Pressure Stage ◽  
Tectonic Coal ◽  
Seepage Characteristics

Coalbed methane is a double-edged sword with two attributes of energy and hazard in coal mines. Gas drainage is the most direct and effective measure for gas recovery and disaster prevention in coal mines, which is seriously affected by the mechanics and seepage characteristics of coal. In this work, we experimentally simulated the triaxial compression and gas depletion processes using both tectonic coal and intact coal. The mechanics and seepage characteristics of tectonic and intact coal under the coupling effect of stress and gas pressure were analyzed and compared. The results show that during the triaxial compression, the damage stress and peak stress of tectonic coal is only half that of intact coal, while their compaction stress or residual stress are almost the same. Meanwhile, the permeability recovery value after tectonic coal failure is very limited, even smaller than that of intact coal, although its primary permeability is much larger than that of intact coal. On the contrary, the permeability recovery value after intact coal failure is more than twice of its primary permeability. During the gas depletion, the rebound gas pressure of tectonic coal is smaller than that of intact coal, and the permeability of tectonic coal is one order of magnitude larger than that of intact coal before the gas pressure drops to 2 MPa. The broken of tectonic coal and the low permeability of intact coal may be the two principal reasons. Therefore, in the tectonic coal area, the gas extraction time at high gas pressure stage should be stabilized, while in the intact coal area, the gas extraction time at low gas pressure stage should be increased, and the coal permeability enhancement measures should be combined to achieve the goal of high and stable production of coalbed methane.

Experimental and Numerical Study of the Influence of Gas Pressure on Gas Permeability in Pressure Relief Gas Drainage

2018 ◽  
Vol 124 (3) ◽  
pp. 995-1015 ◽  
Author(s):  
Cun Zhang ◽  
Lei Zhang ◽  
Shihao Tu ◽  
Dingyi Hao ◽  
Teng Teng
Keyword(s):  
Gas Permeability ◽  
Numerical Study ◽  
Gas Pressure ◽  
Pressure Relief ◽  
Gas Drainage
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