Reinforced Techniques Analysis of Goaf-Side Entry at Isolated Island Coal Face Based on FLAC Numerical Simulation

2012 ◽  
Vol 605-607 ◽  
pp. 210-214 ◽  
Author(s):  
Wen Hua Zha
Keyword(s):  
Surrounding Rock ◽  
Good Effect ◽  
Control Problems ◽  
Rock Stress ◽  
Coal Face ◽  
The Third ◽  
Result Show ◽  
Surrounding Rock Control ◽  
Stress And Deformation ◽  
Surrounding Rock Stress

According to control problems of surrounding rock at isolated island coal face, taking isolated island coal 1251（3）face ventilation tunnel of PanSan mine as engineering background, this paper puts forward three reinforcement schemes based on the idea of turning later recovery to former reinforcement. Simulation has been done on the character of surrounding rock stress and deformation distribution and supporting structure force of three different schemes by FLAC3D. Finally optimal scheme is the third scheme. The application result show that anchor-net-cable support combined with anchor grouting support has got a good effect. The large deformation of surrounding rock is controlled efficiently and tunnel surrounding rock stable is guaranteed. The study provides a basis for goaf-side entry surrounding rock control under similar conditions.

Surrounding Rock Stress and Deformation Evolution Character Analysis of Circular Openings in Deep Underground Engineering

2011 ◽  
Vol 418-420 ◽  
pp. 2001-2005
Author(s):  
Ai Ping Yuan ◽  
Mao Wei Ji ◽  
Dai Qiang Deng
Keyword(s):  
Hard Rock ◽  
Confining Pressure ◽  
Surrounding Rock ◽  
Rock Stress ◽  
Underground Engineering ◽  
High Confining Pressure ◽  
Deep Underground ◽  
Stress And Deformation ◽  
Peak Value ◽  
Surrounding Rock Stress

Hard rock generally performs ideal plastic character after the stress reaches its peak value with high confining pressure. Once the plastic strain satisfies certain condition, the brittle failure occurs, and the rock mass located in the residual region. Based on the mechanical model of hard rock under high confining pressure, we studied the surrounding rock stress and deformation evolution law of circular openings. The results shows that there is a significant end constraint effect at the opening face, and the deformation induced by disturbance is about one sixth of its total value. The results can provide theoritical foundation for deep underground engineer lining design.

The Study of Stress Distribution Law of Roadway Surrounding Rock Heading Advancing Coal Face

2011 ◽  
Vol 361-363 ◽  
pp. 166-170 ◽  
Author(s):  
Jun Ling Hou
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Theoretical Foundation ◽  
Dynamic Pressure ◽  
Surrounding Rock ◽  
Rock Stress ◽  
Coal Face ◽  
Distribution Law ◽  
Computer Numerical Simulation ◽  
Surrounding Rock Stress

In background of the geological engineering and the mining technical conditions of ZhangJi coal mine 17258 fully-mechanized face and rail roadway of 1724 (1) fully-mechanized face,by the field observation and computer numerical simulation studying the stress distribution law of roadway surrounding rock heading advancing coal face.Obtain the influence scope of the dynamic pressure along coal seam trend and tendency, the stress peaks position, perturbation boundary angle of dynamic pressure,and the surrounding rock stress distribution law of roadway excavating in the zone of the stress concentration and stress reduced area. Provides the theoretical foundation for roadway layout under similar conditions.

Field Monitoring of Surrounding Rock Stress in Tunnel Construction

2012 ◽  
Vol 170-173 ◽  
pp. 1735-1739
Author(s):  
Ying Na Dong ◽  
Qiang Huang
Keyword(s):  
Spatial Effect ◽  
Field Monitoring ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Rock Stress ◽  
Vibrating Wire ◽  
Stress Variation ◽  
Stress Changes ◽  
Tunnel Diameter ◽  
Surrounding Rock Stress

The surrounding rock stress field monitor has been done in excavation by vibrating wire transducer. The field monitoring data are compared with numerical simulation results. The result shows: Vibrating wire transducer can record the stress variation of surrounding rock and support. Surrounding rock stress changes violently at every excavation step, such as lower bench excavation, the stress variation is mainly controlled by the spatial effect. When the distance from excavation face to the monitoring section is more than a tunnel diameter, the rock stress variation is mainly affected by time and it is relatively smooth and continuous.

scholarly journals An Experimental Research on Surrounding Rock Unloading during Solid Coal Roadway Excavation

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Hongjun Guo ◽  
Ming Ji ◽  
Dapeng Liu ◽  
Mengxi Liu ◽  
Gaofeng Li ◽  
...  
Keyword(s):  
Energy Storage ◽  
Deformation Energy ◽  
Surrounding Rock ◽  
Dissipated Energy ◽  
Rock Stress ◽  
Deformation And Failure ◽  
Coal Roadway ◽  
Solid Coal ◽  
Unloading Rate ◽  
Surrounding Rock Stress

In order to further explore the deformation and failure essence of the deep coal body, based on the characteristics of surrounding rock stress adjustment before and after solid coal roadway excavation, an experiment of unloading confining pressure and loading axial pressure of the coal body was designed and conducted in this study. Based on test results, the failure mechanics and energy characteristics of the coal body were analyzed through experiments. Rapid unloading is considered a key factor contributing to lateral deformation and expansion failure, which exacerbates the deterioration of coal body and reduces the deformation energy storage capacity of coal. On the other hand, the larger loading rate tends to shorten the accumulation time of microcracks and cause damage to the coal body, resulting in strengthening the coal body and improving energy storage. Under the circumstance that the coal body is destroyed, the conversion rates of the internal deformation energy and dissipated energy are more significantly affected by unloading rate. The increasing unloading rate and rapid decreases in the conversion rate of deformation energy make the coal body more vulnerable to damage. Under the same stress conditions, the excavation unloading is more likely to deform, destroy, or even throw the coal than the experiment unloading. In order to reduce or avoid the occurrence of deep roadway excavation accidents, the understanding of the excavation unloading including possible influencing factors and the monitoring of the surrounding rock stress and energy during the excavation disturbance should be strengthened. It can be used as the basis for studying the mechanism of deformation and failure of coal and rock and dynamic disasters in deep mines, as well as the prediction, early warning, prevention, and control of related dynamic disasters.

scholarly journals Study on Stability of Round Tunnel Surrounding Rock

2018 ◽  
Vol 175 ◽  
pp. 04016
Author(s):  
NIU Yan ◽  
Ji Yafei ◽  
Wang Zhao
Keyword(s):  
Evaluation Criteria ◽  
Surrounding Rock ◽  
Rock Stress ◽  
Stress Release ◽  
Circular Tunnel ◽  
Tunnel Excavation ◽  
Finite Element Software ◽  
Rock Stability ◽  
The Stability ◽  
Surrounding Rock Stress

Tunnel excavation will lead to the immediate surrounding rock unloading caused by the surrounding rock stress release, the stability of the surrounding rock have a certain impact. In this paper, finite element software ANSYS and finite difference software FLAC3D are used to simulate the excavation and lining process of circular tunnel. The influence of excavation on the rock stability around circular tunnel is analyzed, and the effect of applying lining on the stability of surrounding rock is analyzed. Evaluation criteria selection hole displacement, stress and plastic area of three factors.

scholarly journals Stress Evolution Law of Surrounding Rock with Gob-Side Entry Retaining by Roof Cutting and Pressure Release in Composite Roof

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Yong Zhang ◽  
Huichen Xu ◽  
Peng Song ◽  
Xiaoming Sun ◽  
Manchao He ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Surrounding Rock ◽  
Rock Stress ◽  
Dynamic Adjustment ◽  
Pressure Relief ◽  
Middle Point ◽  
Pressure Release ◽  
Whole Process ◽  
Working Face ◽  
Surrounding Rock Stress

The stress concentration of gob-side entry surrounding rock is a hot topic in coal mining. In this paper, through theoretical analysis and numerical simulation, the pressure relief mechanism of the gob-side entry retaining by roof cutting and pressure release (RCPR) and the spatiotemporal development law of surrounding rock stress of the gob-side entry were analyzed. The studies showed that the gob-side entry retaining by RCPR shortened the length of the lateral cantilever by directional roof cutting, which weakened the stress level of the gob-side entry. In the meantime, the goaf gangues could play a good filling role by using their breaking and swelling characteristics under the action of gangue-blocking supports and further optimized the stress environment along the roadway. Field industrial tests verified that the gob-side entry retaining by RCPR had a significant effect on pressure relief, and the surrounding rock stress and deformation tended to stabilize after about 160 m of lagging working face. Numerical analysis reproduced the whole process of “mining-retention-using” of roof cutting roadway and revealed that surrounding rocks were always in the zone of relative stress reduction during the whole process. The peak value of mining-induced lateral stress was about 10 m away from the middle point of the gob-side entry. The change of surrounding rock stress could be divided into three stages: significant increase, dynamic adjustment, and stable stage. However, during the second mining, the stress connected zone would appear on the leading working face, and the stress concentration in this zone was significant. Based on the above analysis, we concluded that the new technology could be applied to the medium-thickness coal seam in the composite roof.

Fluid-Solid Coupling Analysis the Plastic Damage of the Surrounding Rock under the Influence of Confined Water Pressure and Mining Disturbance

2012 ◽  
Vol 616-618 ◽  
pp. 533-537
Author(s):  
Chun Hu Zhao
Keyword(s):  
Water Pressure ◽  
Coupling Model ◽  
Surrounding Rock ◽  
Deformation Characteristics ◽  
Concentration Zone ◽  
Confined Water ◽  
Rock Stress ◽  
Plastic Damage ◽  
Mining Disturbance ◽  
Stress And Deformation

In order to anlysis the rock deformation characteristics in influence of mining disturbances, water pressure and crustal stress, a multi-physics coupling model is created by Comsol4.2a in this paper. By debugging mining steps and water pressure, the model simulated rock stress and deformation characteristics.the results showed that: (1)the water pressure is fixed conditions, the plastic damage scope in stress concentration zone where was formed by mining disturbanceis were greater than the mining floor,and with an extension of the scope of mining, the scope of plastic failure zone in the rock surrounding which including the vertical and horizontal was increased; (2) Stope width is fixed conditions,with the water pressure increases, resulting in the surrounding rock mechanical strength decrease, and increase the scope of the plastic collapse and plastic damage within thefault zone intensified.

scholarly journals Roadway Surrounding Rock under Multi-Coal-Seam Mining: Deviatoric Stress Evolution and Control Technology

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Dongdong Chen ◽  
En Wang ◽  
Shengrong Xie ◽  
Fulian He ◽  
Long Wang ◽  
...  
Keyword(s):  
Plastic Zone ◽  
Coal Seam ◽  
Coal Pillar ◽  
Surrounding Rock ◽  
Deviatoric Stress ◽  
Mine Pressure ◽  
Coal Face ◽  
Surrounding Rock Control ◽  
Seam Mining ◽  
Peak Value

Multi-coal-seam mining creates surrounding rock control difficulties, because the mining of a coal face in one seam can affect coal faces in another. We examine the effects of multi-coal-seam mining on the evolution of the deviatoric stress distribution and plastic zone in the roadway surrounding rock. In particular, we use numerical simulation, theoretical calculation, drilling detection, and mine pressure observation to study the distribution and evolution characteristics of deviatoric stress on Tailgate 8709 in No. 11 coal seam in Jinhuagong mine when the N8707 and N8709 coal faces in No. 7-4 coal seam and the N8707 and N8709 coal faces in No. 11 coal seam are mined. The evolution laws of deviatoric stress and the plastic zone of roadway surrounding rock in the advance and behind sections of the coal face are studied, and a corresponding control technology is proposed. The results show that the peak value of deviatoric stress increases with the advance of the coal face, and the positions of the peak value of deviatoric stress and the plastic zone become deeper. The deflection angle of the peak stress after mining at each coal face and the characteristics of the peak zone of deviatoric stress and the plastic zone of the roadway surrounding rock under the disturbance of multi-coal-seam mining are determined. In conclusion, the damage range in the roadway roof in the solid-coal side and coal pillar is large and must be controlled. A combined support technology based on high-strength and high pretension anchor cables and truss anchor cables is proposed; long anchor cables are used to strengthen the support of the roadway roof in the solid-coal side and coal pillar. The accuracy of the calculated plastic zone range and the reliability of the combined support technology are verified through drilling detection and mine pressure observation on site. This research can provide a point of reference for roadway surrounding rock control under similar conditions.

Research on Fully Mechanized Coal Face Hydraulic Support Selection Based on the Testing Principle of Floor Specific Pressure

2011 ◽  
Vol 217-218 ◽  
pp. 1637-1640
Author(s):  
Nian Jie Ma ◽  
Guo Dong Zhao ◽  
Chun Lei Ju ◽  
Wei Jiang ◽  
Chong Li
Keyword(s):  
Design Optimization ◽  
Surrounding Rock ◽  
Mechanical Parameters ◽  
Specific Pressure ◽  
Crucial Point ◽  
Coal Face ◽  
Hydraulic Support ◽  
Support Design ◽  
Pressure Testing ◽  
Surrounding Rock Control

Interaction between coal face hydraulic support and floor is the crucial point for surrounding rock control in coal face and hydraulic support design optimization. Based on the principle of floor specific pressure testing, mechanized coal face hydraulic support parameters are tracked and such mechanical parameters as allowable specific pressure of floor strata are measured, in accordance with which this paper studies on the surrounding rock control in coal face and hydraulic support selection in fully mechanized coal face.

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