scholarly journals Monitoring and Analysis of Stress Distribution of the Interaction between Rock and Backfill and the Influence of Geometric Features of the Backfill Boundary

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Rong Lu ◽  
Fengshan Ma ◽  
Jie Zhao ◽  
Jianbo Wang ◽  
Guilin Li ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Contact Zone ◽  
Local Stability ◽  
Horizontal Stress ◽  
Field Investigation ◽  
Surrounding Rock ◽  
Geometric Features ◽  
Deep Mining ◽  
Boundary Part ◽  
Distribution Of Stress

Backfill mining methods are widely used in metal mines. The boundary part of the backfill has a direct effect on the local stability in mining engineering. The distribution of stress on the boundary part of the backfill and surrounding rock had their own features. To study the characteristics of stress distribution of backfill and surrounding rock on the boundary part, we conducted a field investigation, field monitoring, and numerical simulation. According to the underground monitoring, the overall characteristics of the boundary part of the backfill were that the accumulated horizontal stress was larger than the accumulated vertical stress on the deep sublevel and the accumulated horizontal stress was smaller on the shallow sublevel. On the contact zone (i.e., the boundary part), the stress of the surrounding rock was larger than the stress of the backfill. Combined with the numerical model analysis, we determined that the geometric features of the backfill boundary had an influence on the stress distribution of stress. The multistep boundary helped the integrity of the contact zone and local stability in deep mining.

scholarly journals Bearing Characteristics of Surrounding Rock of Deep Mining Roadway with Full and End Bolt Anchorages: A Comparative Numerical and Experimental Study

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Wenbao Shi ◽  
Yan Li ◽  
Wanfeng Li ◽  
Shihui Li
Keyword(s):  
Stress Distribution ◽  
Axial Force ◽  
Axial Stress ◽  
Field Tests ◽  
Surrounding Rock ◽  
Deep Mining ◽  
Pull Out ◽  
Laboratory Test Results ◽  
Full Anchorage ◽  
Bolt Support

The support strength of surrounding rock in deep mining roadways can be significantly improved by replacing the end bolt anchorage with a full one. The support effects of both types of anchorage and the axial stress distribution characteristics in anchored bolt bodies were assessed via the indoor pull-out test, simulated via the FLAC3D software, and verified by field measurements. The stability and variation patterns of the axial force, as well as the evolution law of bearing characteristics of surrounding rock, were analyzed. The results indicate that the polymorphic deformations of deep mining roadway surrounding rock and the bolt support body interact synchronously. The axial force evolution trend in bolt bodies with end anchorage revealed by field tests was consistent with the laboratory test results, in contrast to that of full anchorage. Although stress distribution laws in both sides of the mining roadway were the same for both types of anchorage, the vertical stress peak and damage range of full-anchored surrounding rock slightly exceeded those of the end-anchored one. The anchored area bearing a higher load alleviated the stress concentration of the surrounding rock. Since the deformations in fully and end anchored surrounding rocks increased gradually and sharply, respectively, the full anchorage is more conducive to deformation moving control of deep mining roadway surrounding rock. The research results can provide theoretical guidance for the design and construction of deep mining roadway bolt support.

Reasonable Entry Layout of Lower Seam in Multi-Seam Mining Based on Numerical Simulation

2013 ◽  
Vol 295-298 ◽  
pp. 2980-2984
Author(s):  
Xiang Qian Wang ◽  
Da Fa Yin ◽  
Zhao Ning Gao ◽  
Qi Feng Zhao
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Coal Seam ◽  
Coal Mine ◽  
Abutment Pressure ◽  
Surrounding Rock ◽  
Geological Conditions ◽  
Seam Mining

Based on the geological conditions of 6# coal seam and 8# coal seam in Xieqiao Coal Mine, to determine reasonable entry layout of lower seam in multi-seam mining, alternate internal entry layout, alternate exterior entry layout and overlapping entry layout were put forward and simulated by FLAC3D. Then stress distribution and displacement characteristics of surrounding rock were analyzed in the three ways of entry layout, leading to the conclusion that alternate internal entry layout is a better choice for multi-seam mining, for which makes the entry located in stress reduce zone and reduces the influence of abutment pressure of upper coal seam mining to a certain extent,. And the mining practice of Xieqiao Coal Mine tested the results, which will offer a beneficial reference for entry layout with similar geological conditions in multi-seam mining.

Study on the Truss Support Technology for Coal Side in a Soft Broken Coal Roadway Under High Stress

2012 ◽  
Vol 524-527 ◽  
pp. 360-363
Author(s):  
Shou Yi Dong ◽  
Qi Tao Duan ◽  
Fu Lian He ◽  
Qi Li ◽  
Hong Jun Jiang
Keyword(s):  
Production Condition ◽  
High Stress ◽  
Field Investigation ◽  
Surrounding Rock ◽  
Theory Analysis ◽  
Large Section ◽  
Cable Channel ◽  
Coal Roadway ◽  
Measurement Results ◽  
Steel Truss

The coal side deformation and sliding can not be effectively controlled by use of the traditional bolt or cable support in the high stress crushed surrounding rock and large section roadway. For solving this problem, the new prestressed truss support technology is put forward, and its supporting principles of roof and two walls are stated. The mechanical model of cable-channel steel truss is established, and then the tensile strength of the cable and the maximum deflection of the channel steel are derived. By way of field investigation, mechanics theory analysis and actual production condition, the scheme is defined and applied in the replacement roadway. Measurement results of surrounding rock behavior show that the coal side displacement is no more than 254mm and the roof convergence is less than 172mm. Apparent economic and technical profits have been achieved.

scholarly journals Stress distribution in a rectangular plate having two opposing edges sheared in opposite directions

1923 ◽  
Vol 103 (723) ◽  
pp. 598-610 ◽  
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Rectangular Plate ◽  
Royal Society ◽  
External Stress ◽  
The Other ◽  
Optical Methods ◽  
Centre Line ◽  
Distribution Of Stress

The type of deformation under investigation is indicated by fig. 1. A rectangular plate ABCD is deformed into the shape A'B'C'D'. The two opposing edges AB, CD are shifted horizontally without alteration of length into the position A'B', C'D', the other boundaries AD, BC being kept free from external stress. In a paper which appeared in the 'Proc. Royal Society', December 28, 1911, Prof. E. G. Coker investigated this same type of deformation using optical methods to determine the distribution of stress along the centre line OX. He found that if the plate was square the shear stress along OX was distributed in a munner which was approximately parabolic. As the ratio of AD to AB decreased the curve of distribution first of all became flat-topped, and for yet smaller ratios two distinct humps made their appearance.

scholarly journals Stress Distribution Around Mechanized Longwall Face at Deep Mining in Quang Ninh Underground Coal Mine

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Manh Tung BUI ◽  
Tien Dung LE ◽  
Trong Hung VO
Keyword(s):  
Stress Distribution ◽  
Sea Level ◽  
Coal Mine ◽  
Coal Mines ◽  
Longwall Face ◽  
Geological Condition ◽  
Deep Mining ◽  
Roof Fall ◽  
The Impact ◽  
Quang Ninh

Quang Ninh underground coal mines are currently in the phase of finishing up the mineralreserves located near the surface. Also, in this phase, a number of coal mines have opened and preparednew mine sites for the extraction of the reserves at greater depth. Several mines have mined at -350 mdepth and are driving opening excavations at -500 m depth below sea level. The mining at greater depthfaces many difficulties, such as a significant increase in support and excavation pressures. The longwallface pressure is mostly manifested in great magnitude that causes support overloaded and jumped andface spall/roof fall. This paper, based on the geological condition of the Seam 11 Ha Lam coal mine,uses the numerical program UDEC for studying the impact of mining depth on stress distribution aroundthe longwall face. The results show that the deeper the mining is, the greater the plastic deformationzone is. The peak front abutment stress moves closer to the coal wall, mainly concentrating on theimmediate roof and top coal. The top coal is greatly broken, and its bearing capacity is decreased. Somesolutions to the stability of roof strata are proposed, and a proper working resistance of support isdetermined. Additionally, the paper suggests that the starting depth for deep mining in Quang Ninhunderground coal mines should be -350 m below sea level.

scholarly journals Effect of Advancing Direction of Working Face on Mining Stress Distribution in Deep Coal Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yuesong Tang ◽  
Wenchao Sun ◽  
Xin Zhang ◽  
Pengju Liu
Keyword(s):  
Stress Distribution ◽  
Large Scale ◽  
In Situ Stress ◽  
Deep Mining ◽  
Deep Coal Mine ◽  
Working Face ◽  
Geological Conditions ◽  
Original Rock ◽  
High Level

Deep mining has become the normal state of coal mining; compared with the mine with shallow buried depth, the consequent high level of in situ stress and complex distribution have brought severe threats to the stability of the stope and the surrounding rock of the roadway. In this research, taking the 121304 working face of Kouzidong Mine as the engineering background, the characteristics of mining-induced stress distribution under complex in situ stress environment in deep mining are analyzed by using on-site measurement of the original rock stress and mining stress, establishing a theoretical model centered on the middle section of the working face, and establishing large-scale numerical calculation models for different advancing directions. It was found that under deep mining conditions, the maximum stress of the original rock is 25.12 MPa, and the direction is vertical. The advanced influence range of mining stress is about 150 m, and the abutment pressure presents a three-peak distribution characteristic in front of the working face. The research results provide important theoretical guiding value for guiding the mining of coal mines with similar geological conditions.

scholarly journals Experimental Research on Mechanical and Energy Characteristics of Reinforced Rock under Dynamic Loading

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Xinxi Liu ◽  
Yu Li ◽  
Fujun Zhao ◽  
Yanming Zhou ◽  
Weiwei Wang ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Strain Rate ◽  
Dynamic Loading ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Surrounding Rock ◽  
Absorbed Energy ◽  
Energy Characteristics ◽  
Deep Mining ◽  
The Stability

The properties of anchored surrounding rock may vary considerably under complex geological and stress conditions, especially dynamic loading in deep mining. Therefore, comprehensive study of the reinforced mechanism is required to prevent failures associated with deep mining. In this paper, with sandstone as matrix and steel bar as bolt, the dynamic compression test of reinforced rock was carried out by using a 50 mm rod diameter split Hopkinson pressure bar (SHPB) test device. The mechanical and energy characteristics of reinforced rock under dynamic loading were analyzed. The results show that the dynamic strength of reinforced sample is greater than that of unreinforced sample and increases with the increase of the strain rate. The reflected energy and absorbed energy increase with the increase of incident energy, while the transmitted energy increases slightly. The higher the strain rate, the larger the energy dissipation rate and the higher the degree of fragmentation. It shows that the energy dissipation characteristic reflects the internal damage process to some extent. Compared with the results of unreinforced samples, the reflected energy of reinforced samples significantly increases and the absorbed energy will significantly decrease. It can be seen that the bolt can reduce absorbed energy of surrounding rock, thereby improving the stability of roadway surrounding rock. The results may provide reference for the stability of deep roadway and support design.

scholarly journals Effects of seepage and weak interlayer on the failure modes of surrounding rock: model tests and numerical analysis

2019 ◽  
Vol 6 (9) ◽  
pp. 190790
Author(s):  
Jing Hu ◽  
Haijia Wen ◽  
Qilong Xie ◽  
Binyang Li ◽  
Qu Mo
Keyword(s):  
Failure Modes ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Model Tests ◽  
Surrounding Rock ◽  
Modes Of Failure ◽  
Geological Conditions ◽  
Weak Interlayer ◽  
Rock Model ◽  
Distribution Of Stress

The presence of weak interlayers and groundwater are common adverse geological conditions in tunnels. To investigate the modes of failure of rock masses surrounding tunnels owing to weak interlayers and groundwater, model tests and numerical simulations were conducted in this study based on two cases, and a model that considers only the weak interlayer was conducted for comparison. Based on the tests, differences between two models in terms of rock pressure, displacement, cracks and strain were analysed. The results reveal that the presence of groundwater has a significant effect on the space–time distribution of stress, displacement and cracks in the surrounding rock. Furthermore, based on the numerical model, the seepage field was analysed in terms of pore water pressure, permeability and the seepage process to understand the joint action of groundwater and weak interlayer on the failure mechanism of tunnels. The results show that the groundwater and interlayer complement each other to induce the failure mode of the surrounding rock. The water accelerates slip in the interlayer and the development of cracks. Conversely, low strength, muddy weak interlayers serve as the channels of water flow, resulting in deformations and cracks at different locations and different failure modes.

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