scholarly journals Study on the Lagging Support Mechanism of Anchor Cable in Coal Roadway Based on FLAC3D Modified Model

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xiangyu Wang ◽  
Guanghui Wang ◽  
Bowen Wu ◽  
Shuaigang Liu
Keyword(s):  
Failure Criteria ◽  
Modified Model ◽  
Support Mechanism ◽  
Anchor Cable ◽  
Pull Out ◽  
Coal Roadway ◽  
Minimum Principal Stress ◽  
Support Resistance ◽  
Initial Support ◽  
Roadway Deformation

Aiming at the broken failure of anchor cable in the mining roadway roof during the mining process, the lagging support scheme of anchor cable is proposed. Based on the results of indoor anchor cable pull-out test, the Cable element in FLAC3D is modified to realize the extension breaking of anchor cable in the calculation process. Furthermore, the minimum principal stress and volume strain rate mutation point are used as the failure criteria of the anchor cable. Through the comparative analysis of five anchor cable lagging support schemes of 6208 transport tunnel in Wangzhuang Mine Coal, the results demonstrate that the lagging support reduces the initial support resistance of the supporting structure. With the increase of lagging time, the ability of anchor cable to adapt to deformation increases gradually. When the lagging time reaches the gentle area of roadway deformation, its ability to adapt to deformation remains stable. Finally, it was determined that the support should start at 10–15 m of the anchor cable lagging head of the 6208 transport tunnel. Industrial tests show that the lagging support scheme ensures that the anchor cable can withstand a certain deformation, and the support body has no broken failure, which effectively controls the large mining-induced deformation of surrounding rock.

Coupled Supporting of Rock Bolt and Anchor Cable in Large Cross-Section Roadway

2012 ◽  
Vol 256-259 ◽  
pp. 1417-1421 ◽  
Author(s):  
Ren Liang Shan ◽  
Zhen Ting Wei ◽  
Xiang Song Kong ◽  
Ji Jun Zhou ◽  
Yan Liu
Keyword(s):  
Plastic Zone ◽  
Cross Section ◽  
Simulation Analysis ◽  
Site Investigation ◽  
Large Cross Section ◽  
Anchor Cable ◽  
Coal Roadway ◽  
Section Size ◽  
Comprehensive Comparison ◽  
Roadway Deformation

With development of coal mining technology and equipment, the coal roadway section size increases gradually, making roadway more difficult to support. In the paper, the supporting of large cross-section roadway in Hedong mine is studied and roadway excavation supporting process is simulated by FLAC3D. Coal roadway deformation and the problem of original supporting scheme are analyzed including displacement field, stress filed and plastic zone. Several supporting optimizations are proposed combined with site investigation and simulation analysis. And the optimizations are simulated and calculated. By comprehensive comparison, the optimal supporting scheme is obtained and some supporting law in large cross-section roadway is concluded. These are helpful for supporting design in future.

Failure mechanism and constitutive relation for an anchorage segment of an anchor cable under pull-out loading

2020 ◽  
Vol 231 (8) ◽  
pp. 3305-3317 ◽  
Author(s):  
S. R. Wang ◽  
Y. H. Wang ◽  
J. Gong ◽  
Z. L. Wang ◽  
Q. X. Huang ◽  
...  
Keyword(s):  
Failure Mechanism ◽  
Constitutive Relation ◽  
Anchor Cable ◽  
Pull Out

scholarly journals Strong Ground Pressure Mechanism and Control at the Longwall Top Coal Caving with a Single Key Stratum in Goaf

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Ke Yang ◽  
Xiaolou Chi ◽  
Wenjie Liu ◽  
Litong Dou ◽  
Zhen Wei
Keyword(s):  
Structural Model ◽  
Field Measurements ◽  
Directional Hydraulic Fracturing ◽  
Key Stratum ◽  
Ground Pressure ◽  
Working Face ◽  
Support Resistance ◽  
Roadway Deformation ◽  
Longwall Top Coal Caving ◽  
Strong Ground

A strong ground pressure in the multiseam environment manifested by rib spalling and roadway deformation at the fully mechanized working face was assessed by a comprehensive combination of field measurements, physical simulations, and theoretical analysis for two coal seams in the Buertai Coal Mine in China. A structural model of overlying stratum collapse at the working face with the key stratum breaking instability was proposed, the mechanism of strong ground pressure at the longwall top coal caving working face with a single key stratum in goaf was identified, and respective control countermeasures were developed. The latter implied the directional hydraulic fracturing for supporting the key stratum-surrounding rocks, which effectively reduced the cyclic weighting intensity and weighting interval in the working face with a single key stratum in the goaf. The working face cyclic breaking interval was assessed at 30 m. After the key stratum collapse, soft rocks underwent synergistic deformation and a cutting-type failure. The goaf effect on the hydraulic support resistance in the fully mechanized working face was assessed, and cutting blocks from the overlying stratum collapse were identified as the main sources of strong ground pressure.

scholarly journals Experimental Study on Load-Displacement Relationship of Prestressed Cable in Red Clay Stratum

2018 ◽  
Vol 38 ◽  
pp. 03007
Author(s):  
Yong Xing Ji ◽  
Yuan Jie Xiang ◽  
Xiao Yong Zhao
Keyword(s):  
Damage Index ◽  
Theoretical Models ◽  
Exponential Model ◽  
Red Clay ◽  
Anchor Cable ◽  
Pull Out ◽  
S Curve ◽  
Plastic Displacement ◽  
Relationship Of ◽  
Prestressed Anchor

The P-S curves of prestressed anchor cable are obtained by field pull-out tests in the red-clay stratum in Guiyang area. The P-S curves of different theoretical models are discussed base on the theoretical analysis. The elastic and plastic displacement of prestressed anchor cable are analyzed. The results shows that, the anchoring effect are mainly effected by the red-clay mechanic properties in the red-clay stratum; the P-S curve of anchor bolt can be fitted well by the exponential model and conformed to the actual; the plastic displacement is used to anchor’s damage index are more truthfulness in the red-clay stratum.

Research on Spacial Displacement Regulations in Soft Surrounding Rock Tunnel

2013 ◽  
Vol 690-693 ◽  
pp. 886-889
Author(s):  
Bao Long Lin
Keyword(s):  
High Speed ◽  
Surrounding Rock ◽  
Construction Process ◽  
High Speed Rail ◽  
Tunnel Stability ◽  
Construction Methods ◽  
Minimum Principal Stress ◽  
Initial Support ◽  
Rock Tunnel ◽  
Weak Surrounding Rock

Based on the engineering background of Dongkeling tunnel of Guizhou-Guangzhou high-speed rail, construction process in soft surrounding rock is simulated by using finite difference software——FLAC according to large-deformation characteristics in water-rich and weathering altered granite weak surrounding rock. Several aspects, such as vault settlement, invert uplift, clearance convergence, surface settlement, the maximum and minimum principal stress of the initial support and plastic zone of surrounding rock, are analyzed to determine the tunnel stability with different construction methods.

Reliability Analysis for Inserts in Sandwich Composites

2011 ◽  
Vol 275 ◽  
pp. 234-238 ◽  
Author(s):  
Biswajit Banerjee ◽  
Brian G. Smith
Keyword(s):  
Sandwich Panels ◽  
Failure Surface ◽  
Failure Criteria ◽  
Sandwich Composites ◽  
Stress Concentrations ◽  
Pull Out ◽  
Reliability Method ◽  
Honeycomb Sandwich ◽  
Load To Failure ◽  
Reliability Methods

Inserts are used to transfer localized loads to structures made of sandwich composites. Stress concentrations near inserts are known to cause failures in sandwich panels. Experimental insert pull-out tests show that the load to failure can vary by 20% between batches of sandwich panels. Clearly, uncertainties in the mechanical properties of core and adhesive potting materials have to be accounted for in the optimal design of inserts in sandwich composites. In this paper, we use an one-dimensional computational model of an insert in a homogenized honeycomb sandwich panel to explore the utility of reliability methods in design. We show that the first-order reliability method (FORM) produces accurate estimates of loads that lead to low failure probabilities. We also observe that FORM is sensitive to the failure criteria and may not converge if the failure surface is not smooth and convex.

Reasons and Control Countermeasures of Special Soft Coal Roadway Deformation in Liangbei Coal Mine

2013 ◽  
Vol 671-674 ◽  
pp. 1144-1149
Author(s):  
Le Tuan Cheng ◽  
Jia Lin Zhang ◽  
Zheng Sheng Zou ◽  
Qing Bo Li
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Mining Area ◽  
Gas Content ◽  
Deformation And Failure ◽  
Gas Outburst ◽  
Soft Coal ◽  
Coal Roadway ◽  
Roadway Stability ◽  
Roadway Deformation

B1 coal seam located at -550m level in Liangbei Coal Mine is a typical "three-soft" seam. The coal roadway with a depth of 610-750m lies under the critical softening depth of the roadway, and its support difficulty coefficient is 1.5-2.0. The coal has poor air permeability, high gas content and high gas pressure, so danger degree of the gas outburst is relatively strong. The coal seam was destroyed in a disastrous state by more than 100 boreholes for gas outburst prevention during the excavation. This results in the difficulty in the roadway support. Engineering geological characteristics of the coal roadway at 11 mining area are introduced. Based on the engineering geo-mechanics method, the reasons of deformation and failure of the coal roadway are analyzed. In view of problems in excavation and support, as well as the type of the coal roadway deformation mechanism, the borehole parameters are optimized for the gas outburst prevention, and bolt-net-cable coupling support with high convex steel-belt is used to control the coal roadway stability at 11 mining area. Practice shows that the effect is fine.

scholarly journals Wind Fragility for Sign Structure in Korea with Chemical Anchor Connection

2018 ◽  
Vol 186 ◽  
pp. 02008 ◽  
Author(s):  
Viriyavudh Sim ◽  
SeongDo Kim ◽  
WooYoung Jung
Keyword(s):  
Simulation Method ◽  
Failure Criteria ◽  
Dominant Factor ◽  
Strong Wind ◽  
Shear Tests ◽  
Pull Out ◽  
Typical Sign ◽  
Concrete Building ◽  
Sign Structure ◽  
Strong Winds

Damage to domestic facilities by strong winds and typhoon is on the rise in recent year. Typical sign structure used in Korea is found on the edge of concrete building, which could be easily affected by strong winds. Therefore, this study focused on sign structure among various vulnerable facilities. The evaluation of wind fragility for sign structure was carried out considering the failure of anchor at their connection to the concrete building. Moreover, pull-out and shear tests were performed to determine the resistance capacity of anchor used in this study. Monte Carlo Simulation method was used to generate random wind loads on sign structure. Additionally, fragility parameters were determined based on the failure criteria of connection anchor. Results show that diameter of the installed anchor was the dominant factor affecting the performance of sign structure subjected to strong wind.

Stress Distribution Characteristics in Rock Surrounding Heading Face and its Relationship with Temporary Supporting

2014 ◽  
Vol 568-570 ◽  
pp. 1684-1689
Author(s):  
Zhong Han Chen
Keyword(s):  
Coal Mine ◽  
Surrounding Rock ◽  
Zenith Distance ◽  
Rock Stability ◽  
Coal Roadway ◽  
Temporary Support ◽  
The Stability ◽  
Roadway Deformation ◽  
Mine Roof ◽  
Roof Deformation

To solve the problem of underground tunneling face from the empty top, using FLAC3D analysis software, surrounding rock stability for coal roadway 2-1121 of Ganhe Coal Mine are analyzed in numerical calculation. (1) During the tunneling, distance drivage face head-on 0.5-1m at the roof of roadway deformation and destruction features are more obvious, the two sides of roadway are even more significant. (2) Ganhe Coal Mine roof deformation has been established with different empty the experience formula of the zenith distance, obtained Ganhe underground tunneling face reasonable empty zenith distance is 3.5m. (3) Temporary support can obviously reduce roof deformation, reduce thickness of plastic zone of the top, to improve the stability of surrounding rock tunneling faces.

scholarly journals Analytical Solution for the Deformation and Support Parameters of Coal Roadway in Layered Roof Strata

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Kai Wang ◽  
Bao-gui Yang ◽  
Zhong-kui Wang ◽  
Xiao-long Wang
Keyword(s):  
High Efficiency ◽  
Design Method ◽  
Beam Theory ◽  
High Strength ◽  
Failure Criteria ◽  
Key Stratum ◽  
Coal Roadway ◽  
The Stability ◽  
Roof Strata

In order to meet the security and high-efficiency production needs, high-strength bolt (cable) reinforcement technology is usually used to maintain the stability of roadways. However, due to the great variability of lithology and mechanical properties, the failure form and stability of the layered roof in coal roadways are significant differences. The traditional supporting design method of the layered roof support in coal roadways is the engineering analogy method, which depends on experiences rather than theoretical analysis. Based on the theory of the elastic foundation beam and key stratum, this paper establishes a simplified analytical model of layered roof strata in coal roadways. Based on the Mohr-Coulomb theory, this paper gives the failure criteria of the layered roof strata, and the failure range of the layered roof strata is obtained. The length and pretightening force of bolt (cables) of the layered roof strata can be calculated based on the suspension theory and composite beam theory, which providing a quantitative theoretical basis for the determination of supporting parameters. Finally, as a case, the layered roof strata failure range and supporting parameters of the S1301 auxiliary transportation roadway in Gucheng coal mine are calculated.

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