scholarly journals Numerical Simulation of the Supporting Effect of Anchor Rods on Layered and Nonlayered Roof Rocks

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Chao Yuan ◽  
Lei Fan ◽  
Jian-feng Cui ◽  
Wei-jun Wang
Keyword(s):  
Stress Field ◽  
Compressive Stress ◽  
Displacement Field ◽  
Surrounding Rock ◽  
Rock Stress ◽  
Deformation Control ◽  
Original Rock ◽  
Supporting Effect ◽  
Roof Rocks ◽  
Bolt Support

In order to clarify the influence of anchor bolts on the supporting effect of the layered weak roof and surrounding rock of nonlayered roof with good integrity, the mechanical model of the roadway with nonlayered homogeneous roof and layered weak roof was established using FLAC3D. The distribution characteristics of the stress field and the displacement field of the bolt support are analyzed, and the supporting effect of the bolt on the roof of two types of roadways is studied. The research results show that when the original rock stress is not considered, the bolt support shows obvious tensile, compressive stress areas and positive and negative displacement areas in the surrounding rock of the roof of the roadway; when the original rock stress is taken into account, the tensile and compressive stress zones and the positive and negative displacement zones of the anchor support in the surrounding rock of the roof plate disappear obviously. The effect of the bolt support on the stress field and plastic area of the surrounding rock of the two types of roadway roof is not obvious. However, it has a significant effect on suppressing discontinuous deformation such as delamination and sliding between layered roof rocks. The delamination phenomenon between rock layers disappeared obviously, and the range of each numerical curve of the displacement field of the surrounding rock in the anchoring area was significantly reduced. However, the effect of the anchor support on continuous deformation control such as elastoplastic deformation of roof rock of nonlayered roadway is very limited. There is almost no change in the displacement field curve in the depth of the roof-surrounding rock. Only the shallow surrounding rock displacement field curve range has decreased.

Simulation Analysis of the Soft Rock Inclined Shaft Surrounding Rock Control with Different Bolt Support Patterns

2014 ◽  
Vol 988 ◽  
pp. 377-382 ◽  
Author(s):  
Peng Fei Jiang
Keyword(s):  
Compressive Stress ◽  
Simulation Analysis ◽  
Soft Rock ◽  
High Strength ◽  
Surrounding Rock ◽  
Tension Stress ◽  
Deformation And Failure ◽  
Stress And Deformation ◽  
Rock Strata ◽  
Bolt Support

Taking +150 inclined shaft going through the soft rock strata at Muchengjian mine as the background, and based on the analysis of the deformation and failure feature of the roadway surrounding rock in the soft rock strata, this paper makes X-Ray Differaction (XRD) phase analysis of the soft rock; using finite difference numerical software FLAC3D, it stimulates and makes comparative analysis of the stress and deformation distribution characteristics of the roadway surrounding rock with bolt support with different intervals, and the support of the high-strength bolt with high pre-tension stress in the inclined shaft through the soft rock strata. The results show that the roadway surrounding rock in the +150 inclined shaft at Muchengjian mine is swelling soft rock prone to softening, degradation and swelling in water, which is bad for the roadway support; different types of rock strata have significant different impact on the stress and deformation of the roadway surrounding rock; for the soft rock roadway, the increased pre-tension stress of the bolt can cause higher compressive stress in the roadway surrounding rock and reduce the tension failure of the surrounding rock;compared with the end anchorage, the full-size anchorage with high pre-tension stress can cause the overlap of the conical compressive stress zone and enhance the roadway overall support.

scholarly journals Numerical Simulation Research on Distribution Characteristics of Overlying Rock Stress Field in Floor Roadway

2021 ◽  
Vol 257 ◽  
pp. 03024
Author(s):  
Zhonghua Wang
Keyword(s):  
Stress Field ◽  
Field Distribution ◽  
Theoretical Basis ◽  
Surrounding Rock ◽  
Horizontal Distance ◽  
Distribution Characteristics ◽  
Rock Stress ◽  
Simulation Research ◽  
Location Selection ◽  
Coal Roadway

In order to explore the distribution characteristics of the overlying rock stress field in the floor roadway at different locations, FLAC3D software was used to simulate and analyze the surrounding rock directly above the floor roadway and the surrounding rock within 15m on both sides of the floor roadway when the distance between the floor roadway and the coal roadway and the horizontal distance were changed. The stress field distribution characteristics are obtained, and the stress field distribution characteristics of different areas directly above and on both sides of the floor roadway are obtained, which provides a theoretical basis for the location selection and support of the floor roadway.

scholarly journals Sliding Impact Mechanism of Square Roadway Based on Complex Function Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Decheng Ge ◽  
Fuxing Jiang ◽  
Cunwen Wang ◽  
Yang Chen ◽  
Chunyu Dong ◽  
...  
Keyword(s):  
Energy Density ◽  
Plastic Zone ◽  
Elastic Energy ◽  
Surrounding Rock ◽  
Failure Zone ◽  
Rock Stress ◽  
Elastic Energy Density ◽  
Four Corners ◽  
Original Rock ◽  
Shear Slip

To clarify the process of stress change and plastic zone evolution of square roadways under high-stress conditions, the rotational square expansion plastic zone evolution model of square roadway was established by theoretical analysis, numerical simulation, and engineering verification. The shear slip impact stress criterion of square roadway based on complex variable function theory was studied, and the law of surrounding rock stress distribution, plastic zone expansion, elastic energy density, local energy release rate (LERR), and total energy release of square roadway were analyzed. The results show that the compressive stress is concentrated in the four corners of the roadway after the roadway excavated and transfers with the change of plastic zone. Main shear failures start from the four corners and develop in a rotating square shape, forming square failure zones I and II. The square failure zone I is connected with the roadway contour and rotated 45°. The square failure zone II is connected with the square failure zone I and rotated 45°. When the original rock stress is low, the surrounding rock tends to be stable after the square shear slip line field formed. When the original rock stress is high, the shear failure of the surrounding rock continues to occur after the square failure zone II formed, showing a spiral slip line. Corners of the square roadway and square failure zones I and II are the main energy accumulation and release areas. The maximum elastic energy density and LERR increase exponentially with the ratio of vertical stress to uniaxial compressive strength (Ic). When square corners of the roof are changed to round corners, the plastic zone of the roof expands to form an arch structure. The maximum elastic energy density decreases by 22%, which reduces the energy level and possibility of rock burst. This study enriches the failure mechanism of roadway sliding impact. It can provide a basic theoretical reference for the design of the new roadway section and support form based on the prevention of rock burst.

scholarly journals Relationship between advancing abutment pressure and deformation of surrounding rock in a roadway: A case study in Helin coal mine in China

2021 ◽  
Author(s):  
Hongyan Qin ◽  
Zhiheng Cheng ◽  
Zhenhua Ouyang ◽  
Xidong Zhao ◽  
Jicheng Feng
Keyword(s):  
Large Deformation ◽  
Coal Mine ◽  
Abutment Pressure ◽  
Small Deformation ◽  
Surrounding Rock ◽  
Rock Stress ◽  
Deformation Stage ◽  
Original Rock ◽  
Rapid Deformation ◽  
Peak Value

Abstract The deformation stages of the working face of a mine in front of the roadway were defined based on the location of the roadway and the coal wall in different deformation zones. Observational data of the advancing abutment pressure and the surrounding rock deformation of the roadway from Helin coal mine were analyzed using least squares fitting. The results show that the distance between the boundary of the rapid deformation stage and the deceleration deformation stage and the position where the advancing abutment pressure is equal to the original rock stress is 0.8 m. The distance between the boundary of the large deformation stage and the stable small deformation stage and the peak value of the advancing abutment pressure is 0.3 m. A theoretical analysis indicated that the boundary between the rapid deformation stage and the deceleration deformation stage is located at the intersection of the advancing abutment pressure curve and the original rock stress curve. The boundary between the large deformation stage and the stable small deformation stage is located at the peak value of the advancing abutment pressure.

scholarly journals Study on the Stability of a Transition Section from Soft to Hard Surrounding Rock Based on the Solid-Fluid Coupling Effect

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Qizhi Hu ◽  
Yixin Tang ◽  
Zhigang Ding
Keyword(s):  
Stress Field ◽  
Displacement Field ◽  
Coupling Effect ◽  
Surrounding Rock ◽  
Guizhou Province ◽  
Seepage Field ◽  
Support Structure ◽  
Transition Section ◽  
Design Values ◽  
The Stability

To study the stability of a transition section of a tunnel from soft to hard surrounding rock under seepage conditions, FLAC3D software was used to numerically simulate the transition section of the Laomushan Tunnel from the Shiqian to Yuping (Dalong) Expressways in Guizhou Province, China, and to explore different working conditions. The characterization of the tunnel seepage field, stress field, and displacement field and the analysis of the force of the primary lining support structure describe the influence of the seepage field on the stress field distribution and displacement field changes. The reliability of the calculation results is verified by comparison with displacement measurements collected during field monitoring. The design values of the primary support structure parameters of the transition section from soft to hard surrounding rock of the Laomushan Tunnel basically met the strength requirements. The research results provide references for the design and construction of similar projects.

scholarly journals Displacement of surrounding rock in a deep circular hole considering double moduli and strength-stiffness degradation

2020 ◽  
Vol 41 (12) ◽  
pp. 1847-1860
Author(s):  
Zenghui Zhao ◽  
Wei Sun ◽  
Shaojie Chen ◽  
Yuanhui Feng ◽  
Weiming Wang
Keyword(s):  
Stress Field ◽  
Plastic Region ◽  
Surrounding Rock ◽  
Constitutive Relationship ◽  
Stiffness Degradation ◽  
Flow Rule ◽  
Constant Modulus ◽  
Underground Engineering ◽  
Dilatancy Angle ◽  
Original Rock

AbstractThe problem of cavity stability widely exists in deep underground engineering and energy exploitation. First, the stress field of the surrounding rock under the uniform stress field is deduced based on a post-peak strength drop model considering the rock’s characteristics of constant modulus and double moduli. Then, the orthogonal non-associative flow rule is used to establish the displacement of the surrounding rock under constant modulus and double moduli, respectively, considering the stiffness degradation and dilatancy effects in the plastic region and assuming that the elastic strain in the plastic region satisfies the elastic constitutive relationship. Finally, the evolution of the displacement in the surrounding rock is analyzed under the effects of the double moduli characteristics, the strength drop, the stiffness degradation, and the dilatancy. The results show that the displacement solutions of the surrounding rock under constant modulus and double moduli have a unified expression. The coefficients of the expression are related to the stress field of the original rock, the elastic constant of the surrounding rock, the strength parameters, and the dilatancy angle. The strength drop, the stiffness degradation, and the dilatancy effects all have effects on the displacement. The effects can be characterized by quantitative relationships.

Research on Geostatic Stress and Optimization of Bolt Support for Tilted Strata Roadway

2014 ◽  
Vol 580-583 ◽  
pp. 1335-1341 ◽  
Author(s):  
Ren Liang Shan ◽  
Liang Tian ◽  
Wen Feng Zhao ◽  
Jin Yang Lv ◽  
Yu Hang Xiao ◽  
...  
Keyword(s):  
Rock Stress ◽  
Numerical Computations ◽  
Support Design ◽  
Geological Conditions ◽  
Measurement And Analysis ◽  
Original Rock ◽  
Roadway Deformation ◽  
Support Methods ◽  
Bolt Support

In order to tunnel safely, efficiently and economically, we carried out the study on geostatic stress characters and optimizing bolting support parameters in 2# coalbed of Zijin Colliery. Based on the surveys of geological conditions, original rock stress, broken rock zone measurement and analysis of roadway deformation, characters and mechanism of roadway failure is figured out. According to existent problems, normal support theories were used and a variety of numerical computations were carried out by FLAC3D.New support methods of bolt installed vertically in tilted roof and strengthen support of sidewalls and corners of roadway were figured out. Monitoring of convergence meters and roof separation were followed to know effects of new design timely. The research was carried out for 600 meters The monitoring results proved that the optimized support design was viable and the new bolting parameters were reasonable.

scholarly journals Comprehensive technical support for safe mining in ultra-close coal seams: A case study

2021 ◽  
pp. 014459872110093
Author(s):  
Wei Zhang ◽  
Jiawei Guo ◽  
Kaidi Xie ◽  
Jinming Wang ◽  
Liang Chen ◽  
...  
Keyword(s):  
Coal Seam ◽  
Technical Support ◽  
Surrounding Rock ◽  
Coal Seams ◽  
Deformation Control ◽  
Hard Roof ◽  
Working Face ◽  
Close Coal Seams ◽  
Safe Mining

In order to mine the coal seam under super-thick hard roof, improve the utilization rate of resources and prolong the remaining service life of the mine, a case study of the Gaozhuang Coal Mine in the Zaozhuang Mining Area has been performed in this paper. Based on the specific mining geological conditions of ultra-close coal seams (#3up and #3low coal seams), their joint systematic analysis has been performed, with the focus made in the following three aspects: (i) prevention of rock burst under super-thick hard roof, (ii) deformation control of surrounding rock of roadways in the lower coal seam, and (iii) fire prevention in the goaf of working face. Given the strong bursting tendency observed in upper coal seam and lower coal seam, the technology of preventing rock burst under super-thick hard roof was proposed, which involved setting of narrow section coal pillars to protect roadways and interleaving layout of working faces. The specific supporting scheme of surrounding rock of roadways in the #3low1101 working face was determined, and the grouting reinforcement method of local fractured zones through Marithan was further proposed, to ensure the deformation control of surrounding rock of roadways in lower coal seams. The proposed fire prevention technology envisaged goaf grouting and spraying to plug leaks, which reduced the hazard of spontaneous combustion of residual coals in mined ultra-close coal seams. The technical and economic improvements with a direct economic benefit of 5.55 million yuan were achieved by the application of the proposed comprehensive technical support. The research results obtained provide a theoretical guidance and technical support of safe mining strategies of close coal seams in other mining areas.

scholarly journals Evolution Pattern and Matching Mode of Precursor Information about Water Inrush in a Karst Tunnel

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1579
Author(s):  
Jie Song ◽  
Diyang Chen ◽  
Jing Wang ◽  
Yufeng Bi ◽  
Shang Liu ◽  
...  
Keyword(s):  
Rock Mass ◽  
Stress Field ◽  
Displacement Field ◽  
Water Inrush ◽  
Seepage Field ◽  
Karst Tunnel ◽  
Rock Mass Structure ◽  
Evolution Pattern ◽  
Water Blocking ◽  
Precursor Information

The water inrush of the Shangjiawan karst tunnel is used to study the evolution pattern of precursor water inrush information in water-filled caves and to further reveal the matching mode of the information. The three-dimensional numerical method FLAC3D was used to simulate the evolution process of water inrush after damage to a water-blocking rock mass structure in a water-filled cave and to obtain the evolution pattern of precursor water-inrush information caused by the damage. The results show that the multifield response to the characteristic precursor information of the water-inrush pattern after the fracture of the water-blocking rock mass follows the order of stress-field displacement-field seepage-field. Further, the matching pattern of the information shows that the stress field increased first and then decreased, the displacement field always increased, and the seepage field increased first and then decreased.

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.

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