Stability Prediction of Surrounding Rocks and Optimum Design of Roof-Bolt Parameters in Deep Roadway

2013 ◽  
Vol 353-356 ◽  
pp. 436-439
Author(s):  
De Sen Kong ◽  
Yong Po Chen
Keyword(s):  
Prediction Method ◽  
Simulation Method ◽  
Complex Stress ◽  
Roof Bolt ◽  
Deformation And Failure ◽  
Long Run ◽  
Research Findings ◽  
Stress Environment ◽  
Classification Prediction ◽  
The Stability

In order to forecast the stability of deep roadway and optimize the parameters of bolts, the complex stress environment and the multivariate surrounding rocks characteristics of deep roadway were analyzed. Then the classification prediction method and the numerical simulation method were simultaneously used to analysis the stability of surrounding rocks. Furthermore, the supporting parameters of bolts were also designed optimally. It was shown that the characteristics of stress distribution, deformation and failure zone of surrounding rocks are not ideal. So it is necessary to optimize the supporting parameters of deep roadway. All these research findings will provide the theory basis for bolts of deep roadway and will ensure the optimization of bolts and the stability of deep roadway in the long run.

scholarly journals Stabilization Mechanism and Safety Control Strategy of the Deep Roadway with Complex Stress

2020 ◽  
Vol 2020 ◽  
pp. 1-18 ◽  
Author(s):  
Yang Yu ◽  
Dingchao Chen ◽  
Xiangqian Zhao ◽  
Xiangyu Wang ◽  
Lianying Zhang ◽  
...  
Keyword(s):  
Plastic Zone ◽  
Control Strategies ◽  
Pressure Coefficient ◽  
Horizontal Stress ◽  
Complex Stress ◽  
Rock Stratum ◽  
Safety Control ◽  
Coal Resources ◽  
Stress Environment ◽  
The Stability

With the increase of mining intensity of coal resources, some coal mines in China have gradually entered the deep mining stage. The complexity of the stress environment of the deep rock stratum leads to the difficulty of coal mining. Among them, the control of the deep roadway is one of the bottlenecks restricting the safety mining of the deep coal resources in China. By means of statistical analysis, the factors affecting the stability of the deep roadway were summed up: roadway occurrence environment, driving disturbance, and support means. The mechanical model of the deep roadway was established with the theory of elastic-plastic mechanics, the distribution characteristics of the plastic zone of the roadway were revealed, and the influence laws of lateral pressure coefficient, vertical stress, and support strength on the stability of the roadway were analyzed. Through numerical simulation, the law of stress, displacement and the plastic zone distribution evolution of the deep roadway, the mechanism of horizontal stress, and the mechanism of bolt support on the roadway were studied. On this basis, the safety control strategies to ensure the stability of the deep roadway were put forward: improving the strength of the roof and floor, especially the bearing part of the top angle and the side angle, enhancing the stability of the two sides of the roadway and controlling the floor heave, and making the surrounding rock of the deep roadway release pressure moderately, so as to make the roadway easy to be maintained under the low stress environment. These meaningful references were provided for the exploitation of deep coal resources in China.

Calculation and Optimization of Soil Slope Stability on One Iron Mine

2014 ◽  
Vol 644-650 ◽  
pp. 1998-2002
Author(s):  
Shi Qing Nan ◽  
Juan Xia Zhang ◽  
Xian Zhang Guo ◽  
Tian Hong Yang
Keyword(s):  
Slope Stability ◽  
Slope Angle ◽  
Simulation Method ◽  
Open Pit ◽  
Open Pit Mining ◽  
Soil Slope ◽  
Deformation And Failure ◽  
Main Research ◽  
Iron Mine ◽  
The Stability

The purpose of slope stability evaluation was that, according to the slope engineering condition and constraints of mining technology, to study the deformation and failure rule of slope occurred by the change of stress field during the open-pit mining. The main research object of the paper was open-pit slope of one iron mine, for the mechanical parameters of the slope, it was obtained by physical experiments, and the numerical simulation method was used for the stability analysis and evaluation of quaternary soil slope angle and final slope angle. And some measures were proposed for slope stability during construction to ensure safety in production. The research of the paper has certain reference significance for optimization calculation of the soil slope stability

scholarly journals Spatial and Temporal Distribution Law and Influencing Factors of the Mining-Induced Deformation and Failure of Gas Boreholes

2018 ◽  
Vol 2018 ◽  
pp. 1-15
Author(s):  
Fei Xue ◽  
Xiaowei Feng
Keyword(s):  
Numerical Simulation ◽  
Temporal Distribution ◽  
Simulation Method ◽  
Mining Area ◽  
Coal Face ◽  
Distribution Law ◽  
Deformation And Failure ◽  
Shear Stability ◽  
Hole Position ◽  
The Stability

Because gas boreholes are easy to damage by integrated coal mining and gas exploration, based on the practice of relieving pressure in deep thin coal seams in the Huainan mining area, a multidimensional coupling numerical simulation method was used to reveal the space-time evolution characteristics and influence factors of fracture deformation of gob-side gas boreholes. Results indicate that the danger zone for borehole fractures is primarily between 5 and 12 m above the roof of the roadway. The final-hole position has little effect on the stability of boreholes, and migrating the open-hole position to the entity coal side and roadway roof side can improve the stability of the borehole. The initial failure of the borehole occurs at a distance of 10 m behind the coal face. The failure of the borehole is largely stable at a distance of 100 to 120 m behind the coal face. With the increase in mining height, which leads to an increase in the movement of strata and an increase in pressure relief range, the shear stability of the borehole is reduced, and the extrusion stability of the borehole is improved. A hard roof condition promotes borehole shear stability, while a weak roof condition promotes borehole extrusion stability. This change can decrease the maintenance difficulty associated with “minor supports” in boreholes to a certain extent by reinforcing the support strength of “primary supports” in roadway retaining walls. The simulation results are consistent with observed results for the 11 test boreholes, and the accuracy of the numerical simulation is verified.

Supporting Technics of Easily Mudding and Ultrahigh Roadway in Soft Coal Rock

2014 ◽  
Vol 988 ◽  
pp. 211-217 ◽  
Author(s):  
Zhen Zhang
Keyword(s):  
Simulation Method ◽  
Field Application ◽  
Structure Stability ◽  
Deformation And Failure ◽  
Soft Coal ◽  
Floor Heave ◽  
Coal Rock ◽  
Stress Environment ◽  
Roadway Deformation ◽  
Two Sides

According to the situation of the great height wall, soft and weak surrounding rocks and sliming characteristics of the 15# coal west-third panel sump in the Gushuyuan mine, the deformation characteristics and mechanism of the sump were analyzed by field survey, laboratory tests and the numerical simulation method. The results show that the sump deformation and failure were determined by its low strength, weakness structural, sliming characteristics and excavation disturbance. The roadway deformation occurs mainly in the middle, upper and lower of the sides and the floor. A comprehensive solution is proposed, including sealing surrounding rocks, strengthening soft and weak surrounding rocks, strengthening the structure stability, improving the surrounding rocks stress environment. This method was applied in the coal mine. Field application results show that this method was suitable for control sump deformation, the maximum roadway roof subsidence is 15 mm, the two sides convergence is 30mm, and the maximum amount of floor heave is 21mm.

scholarly journals Numerical Simulation on the Stability of Surrounding Rock of Horizontal Rock Strata in the Tunnel

2018 ◽  
Vol 3 (12) ◽  
pp. 1189 ◽  
Author(s):  
Nian Zhang ◽  
Weihong Wang ◽  
Zhuoqiang Yang ◽  
Jianian Zhang
Keyword(s):  
Numerical Simulation ◽  
Reference Value ◽  
Simulation Method ◽  
Vertical Displacement ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Geological Condition ◽  
Deformation And Failure ◽  
The Stability ◽  
Rock Strata

Horizontal rock strata is a geological condition of rock which is often encountered in the tunnel construction, and it has an important influence on the tunnel construction, it is necessary to analyze and study the stability of horizontal rock strata in tunnel construction to ensure the tunnel construction’s safety and efficiency. By taking “Xishan Highway Tunnel” as the research object, and using the numerical simulation method, the numerical model of the tunnel has been established in the Midas/GTS to simulate the tunnel excavation under the horizontal rock strata condition，and the deformation and failure mechanism of surrounding rock and the influence factors of surrounding rock stability after are studied and analyzed. The research focused on the displacement of surrounding rock horizontal and vertical deformation, the results show that the vertical displacement of the surrounding rock is obviously greater than that of other parts during the excavation of the horizontal rock tunnel. According to the calculation results, the optimization measures of horizontal stratum tunnel construction method are put forward, which has important reference value for ensuring the construction safety and construction quality.

Improved Burn-In Stress Methodology for Stress Uniformity

2018 ◽  
Author(s):  
Jungsuk Ko ◽  
Hoonchang yang ◽  
Hyungchae Jeon ◽  
Gyuyoung Nam ◽  
Youngseok Ryu ◽  
...  
Keyword(s):  
Temperature Stress ◽  
Stress Condition ◽  
Temperature Deviation ◽  
Stress Effects ◽  
Hot Temperature ◽  
Production Environments ◽  
Stress Environment ◽  
The Stability ◽  
Stress Uniformity ◽  
Stress Voltage

Abstract The necessity of hot temperature stress is widely recognized as the initial stress methodology to maintain the stability of products from infant defects in device [1, 2]. However, hot temperature stress has a disadvantage in terms of stress uniformity because temperature variation according to stress environment such as chamber, board, and tester accelerates different stress effects per chips. In addition, this stress condition can cause serious reliability problem in the mass production environments. Therefore, the stress temperature should be lowered to minimize the temperature deviation due to the production environments. The reduction of stress temperature cause the lack of stress amount, so optimized stress voltage and time to maintain the stress condition is required. In this study, various stress voltage and time with decreasing temperature were evaluated in consideration of lifetime that unit elements such transistors and capacitors did not degrade by any stress conditions. In addition, it was confirmed that stress uniformity can be improved in the stress condition obtained by the evaluation. Furthermore, the enhanced initial failure screen ability was proven with mass evaluations.

scholarly journals Competing Conventions with Costly Information Acquisition

Games ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 53
Author(s):  
Roberto Rozzi
Keyword(s):  
Information Acquisition ◽  
Evolutionary Model ◽  
Equilibrium Selection ◽  
The Other ◽  
Group Interactions ◽  
Social Coordination ◽  
Long Run ◽  
Stochastic Stability Analysis ◽  
The Stability ◽  
The Cost

We consider an evolutionary model of social coordination in a 2 × 2 game where two groups of players prefer to coordinate on different actions. Players can pay a cost to learn their opponent’s group: if they pay it, they can condition their actions concerning the groups. We assess the stability of outcomes in the long run using stochastic stability analysis. We find that three elements matter for the equilibrium selection: the group size, the strength of preferences, and the information’s cost. If the cost is too high, players never learn the group of their opponents in the long run. If one group is stronger in preferences for its favorite action than the other, or its size is sufficiently large compared to the other group, every player plays that group’s favorite action. If both groups are strong enough in preferences, or if none of the groups’ sizes is large enough, players play their favorite actions and miscoordinate in inter-group interactions. Lower levels of the cost favor coordination. Indeed, when the cost is low, in inside-group interactions, players always coordinate on their favorite action, while in inter-group interactions, they coordinate on the favorite action of the group that is stronger in preferences or large enough.

Braucht die EU einen flexibleren Stabilitätspakt?

2004 ◽  
Vol 53 (1) ◽  
Author(s):  
Carsten Hefeker ◽  
Friedrich Heinemann ◽  
Klaus F. Zimmermann
Keyword(s):  
Public Awareness ◽  
Time Lag ◽  
Fiscal Rules ◽  
External Control ◽  
Public Expenditures ◽  
Stability And Growth Pact ◽  
Consolidation Process ◽  
Growth Pact ◽  
Long Run ◽  
The Stability

AbstractIn his contribution Carsten Hefeker points out that most of the official arguments concerning the necessity of the Stability and Growth Pact are not convincing. Nevertheless, a mechanism that credibly avoids excessive debts and deficits is needed in most member states. It would be more useful, however, if such rules would focus on overall debt rather than on deficits. In addition, he advocates to create an external control for such fiscal rules, independent from the Commission and ECOFIN. He concludes that the Pact does not need to become more flexible, but more credible.Friedrich Heinemann states that much of the recent reform debate on the Stability Pact is based on a fundamental misconception: The Pact has not been established as a guiding tool for welfare - maximising politicians, but in order to limit detrimental incentives from fiscal short-sightedness. “Stupid” elements like the three-per-cent deficit ceiling have a clear and beneficial strategic function as boundary within the national budgetary process. Furthermore, simple rules are superior to smart ones in increasing the political costs of high deficits in terms of public awareness. The critique on the pact′s missing flexibility is correct mainly regarding its lose logical link to long-run sustainability. Increasing flexibility in a cyclical sense, however, is not a reform priority. Already today the Pact leaves sufficient leeway for responsible politicians. Instead, the reform focus must be on depoliticising the pact in the sense of limiting Council power in the deficit procedure. More flexibility must not come without depoliticising. He recommends that any reform should only be carried into effect with a significant time lag in order to limit the reputation damage which would be the consequence of any quick institutional response to the Pact′s recent crisis.In his paper Klaus F. Zimmermann argues that the Stability and Growth Pact (SGP) has been subject to criticism ever since its inception. He points out that it overlooks business cycle developments within the framework of the consolidation process; it adopts a too short-term view of the stabilisation target which is also hardly under control of policy-makers; and it deals with policy imperfections in a sub-optimal way. Therefore, a reform of the SGP is urgent. The author suggests that the rules must be handled more flexibly. In his opinion, a mediumterm budgetary target and a focus on public expenditures to tackle the pro-cyclical bias is needed. To restore credibility, the task of supervision should be transferred to an independent European institution.

Mechanism Analysis of Anchor Bolt and Cable Synergistic Action in Coal Roadway Support

2014 ◽  
Vol 716-717 ◽  
pp. 735-738 ◽  
Author(s):  
Peng Cheng ◽  
Jian Zhang ◽  
Ai Qing Liu
Keyword(s):  
Simulation Method ◽  
Paper Analysis ◽  
Synergistic Action ◽  
Mechanism Analysis ◽  
Anchor Bolt ◽  
Tension Distribution ◽  
Coal Roadway ◽  
Cable Force ◽  
Roadway Support ◽  
The Stability

Aiming at the current situation of anchor bolt and cable arrangement in mine roadway support, the paper analysis the mechanical characteristics and mechanism of bolts and cables, and numerical simulation method is used to comparison and analysis of pre-tension distribution characteristics under different anchor bolt-cable arrangement. The research indicated that separate anchor bolt-cable layout in different sections, anchor bolt and cable force stable equilibrium, coordinate with each other, at this time roadway surrounding rock of shallow and deep pretension distribution more reasonable, can play a role of bolt anchor cable synergistic action, and form the best pre-tension load-bearing structure, which is helpful to keep the stability of coal roadway.

scholarly journals CAN f(R) GRAVITY MIMIC GENERAL RELATIVITY?

2012 ◽  
Vol 10 ◽  
pp. 63-68 ◽  
Author(s):  
JE-AN GU
Keyword(s):  
General Relativity ◽  
Differential Equations ◽  
Early Time ◽  
Einstein Equations ◽  
Modified Theories Of Gravity ◽  
Cosmological Perturbations ◽  
Long Run ◽  
Theories Of Gravity ◽  
The Stability ◽  
Higher Order Differential Equations

We discuss the stability of the general-relativity (GR) limit in modified theories of gravity, particularly the f(R) theory. The problem of approximating the higher-order differential equations in modified gravity with the Einstein equations (2nd-order differential equations) in GR is elaborated. We demonstrate this problem with a heuristic example involving a simple ordinary differential equation. With this example we further present the iteration method that may serve as a better approximation for solving the equation, meanwhile providing a criterion for assessing the validity of the approximation. We then discuss our previous numerical analyses of the early-time evolution of the cosmological perturbations in f(R) gravity, following the similar ideas demonstrated by the heuristic example. The results of the analyses indicated the possible instability of the GR limit that might make the GR approximation inaccurate in describing the evolution of the cosmological perturbations in the long run.

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