Study of the Trellis Support of Working Face Roadway in Impact Coal Seam

2014 ◽  
Vol 941-944 ◽  
pp. 2558-2564
Author(s):  
Yu Kai Lv ◽  
Cong Jiang ◽  
Yao Dong Jiang
Keyword(s):  
In Situ Stress ◽  
Surrounding Rock ◽  
Mine Pressure ◽  
Working Face ◽  
Coal Bumps ◽  
Roadway Support ◽  
The Stability ◽  
The Impact ◽  
Physical And Mechanical Characteristics

Coal bumps happened many times in mining at No.5 seam of Tangshan coal mine. Strengthen the roadway’s support of working face can effectively reduce disaster losses. With the research background of the 3654 working face, the mine pressure monitoring for the existing support form of roadway has been carried on. Perform a numerical simulation for the original roadway support, base on the in-situ stress and physical and mechanical characteristics of surrounding rock in experimental; study the impact of the stability of roadway’s surrounding rock, while the space change of trellis and change of supporting intensity; optimizing the original support form, so as to maximum reducing the impact of the coal bumps.

Study on Deformation and Damage of Rock Mass Subject to High In Situ Stress by Using a Elastoplastic Damage Model and Considering the Impact of Weak Planes

2013 ◽  
Vol 838-841 ◽  
pp. 705-709
Author(s):  
Yun Hao Yang ◽  
Ren Kun Wang
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Damage Model ◽  
Back Analysis ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
High In Situ Stress ◽  
Underground Caverns ◽  
The Impact

Large scale underground caverns are under construction in high in-situ stress field at Houziyan hydropower station. To investigate deformation and damage of surrounding rock mass, a elastoplastic orthotropic damage model capable of describing induced orthotropic damage and post-peak behavior of hard rock is used, together with a effective approach accounting for the presence of weak planes. Then a displacement based back analysis was conducted by using the measured deformation data from extensometers. The computed displacements are in good agreement with the measured ones at most of measurement points, which confirm the validities of constitutive model and numerical simulation model. The result of simulation shows that damage of surrounding rock mass is mainly dominated by the high in-situ stress rather than the weak planes and heavy damage occur at the cavern shoulders and side walls.

scholarly journals The Research on Stability of Surrounding Rock in Gob-side Entry Driving in Deep and Thick Seam

2021 ◽  
Author(s):  
jianjun SHI ◽  
Feng Jicheng ◽  
Peng Rui ◽  
Zhu Quanjie
Keyword(s):  
Stability Study ◽  
Surrounding Rock ◽  
Support Pressure ◽  
Thick Coal Seam ◽  
Thick Seam ◽  
Working Face ◽  
Pressure Area ◽  
Roadway Support ◽  
The Stability ◽  
Bolt Steel

Abstract The gob-side entry driving is driving in low pressure area, which bears less support pressure and is easy to maintain, so it is widely used. Taking the gob-side entry driving in thick coal seam of Dongtan Coal Mine as an example, the reasonable size of pillar and the section of roadway are numerically simulated by combining numerical with measurement, and the roadway support is designed. According to the distribution of lateral stress in working face, eight pillars of different sizes are designed. By simulating and comparing the stress distribution of surrounding rock and the development range and shape of plastic zone in different positions, the pillar size of gob-side entry driving is optimized to be 4.5m. According to the results of optimization of roadway section, the section of straight wall semi-circular arch roadway is adopted. According to the analysis, the roadway is supported by bolt + steel mesh + anchor cable. By observing the stability of roadway, it provides experience for the stability study of roadway the gob-side entry driving with small pillar in thick seam.

scholarly journals Evaluation of the Influence of In Situ Stress on the Stability of Mine Pit Walls: A Case Study of Songwe Mine

2021 ◽  
Vol 4 (2) ◽  
pp. p1
Author(s):  
Dyson Moses ◽  
Hideki Shimada ◽  
Takashi Sasaoka ◽  
Akihiro Hamanaka ◽  
Tumelo K. M Dintwe ◽  
...  
Keyword(s):  
Active Regions ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
Slope Instability ◽  
Open Pit ◽  
Stress Regime ◽  
Tectonically Active ◽  
The Stability ◽  
The Impact

The investigation of the influence of in situ stress in Open Pit Mine (OPM) projects has not been accorded a deserved attention despite being a fundamental concern in the design of underground excavations. Hence, its long-term potential adverse impacts on pit slope performance are overly undermined. Nevertheless, in mines located in tectonically active settings with a potential high horizontal stress regime like the Songwe mine, the impact could be considerable. Thus, Using FLAC3D 5.0 software, based on Finite Difference Method (FDM) code, we assessed the role of stress regimes as a potential triggering factor for slope instability in Songwe mine. The results of the evaluated shearing contours and quantified strain rate and displacement values reveal that high horizontal stress can reduce the stability performance of the pit-wall in spite of the minimal change in Factor of Safety (FoS). Since mining projects have a long life span, it would be recommendable to consider “in situ stress-stability analyses” for OPM operations that would be planned to extend to greater depths and those located in tectonically active regions.

scholarly journals EFFECT OF BLASTING ON THE STABILITY OF LINING DURING EXCAVATION OF NEW TUNNEL NEAR THE EXISTING TUNNEL

2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Tuan Minh Tran ◽  
Quang Huy Nguyen
Keyword(s):  
Field Data ◽  
Damage Zone ◽  
Field Tests ◽  
Surrounding Rock ◽  
In Situ Test ◽  
The Stability ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

In recent years, experimental and numerical researches on the effect of blasting pressure on the stability of existing tunnels was widely obtained. However, the effect of the blasting pressure during excavation a new tunnel or expansion old tunnels on an existing tunnel has disadvantages and still unclear. Some researches were carried out to study the relationship of the observed Peak Particle Velocity (PPV) on the lining areas along the existing tunnel direction, due to either the lack of in situ test data or the difficulty in conducting field tests, particularly for tunnels that are usually old and vulnerable after several decades of service. This paper introduces using numerical methods with the field data investigations on the effect of the blasting in a new tunnel on the surrounding rock mass and on the existing tunnel. The research results show that not only predicting the tunnel lining damage zone under the impact of blast loads but also determination peak maximum of explosion at the same time at the surface of tunnel working.

scholarly journals Research and Application of Directional Roof Cutting and Pressure Releasing Technology for Retracement Channel of 3314 Working Face in Hexi Coal Mine

2021 ◽  
Author(s):  
Jindong Cao ◽  
Xiaojie Yang ◽  
Ruifeng Huang ◽  
Qiang Fu ◽  
Yubing Gao
Keyword(s):  
Coal Mine ◽  
High Stress ◽  
Surrounding Rock ◽  
Engineering Practice ◽  
Mine Pressure ◽  
Working Face ◽  
Geological Conditions ◽  
Cutting Effect ◽  
The Stability ◽  
Two Sides

Abstract The high stress of the surrounding rock of Hexi Coal Mine easily leads to severe deformation of the retracement channel and the appearance of the mine pressure during the retreat severely affects the stability of the roadway. In order to solve the above problems, a roadway surrounding rock control technology is proposed and tested. The bidirectional energy-concentrated tensile blasting technology is used to perform directional cutting to cut off the stress propagation path. Firstly, the deformation mechanism of the roof is analyzed by establishing the deformation mechanical model of the roof of the retracement channel. Then, according to the geological conditions of working face 3314 and theoretical calculation, the key parameters of roof cutting and pressure releasing of retracement channel are determined, and through the numerical analysis of its cutting effect, the length of cutting seam is 11.5m, and the cutting angle is 10°. Finally, a field test is carried out on the retracement channel of 3314 working face to verify the effect of roof cutting. The results show that the deformation of the retracement channel and the main roadway is very small. In the process of connecting the working face and the retracement channel, the maximum roof to floor convergence is 141mm, and the two sides convergence is 79mm. After the hydraulic support was retracted, the maximum roof to floor convergence of the surrounding rock is 37 mm, and the two sides convergence is 33mm. The roof cutting and pressure releasing of the retracement channel ensures the safe evacuation of the equipment and the stability of the main roadway. The cutting effect is obvious for the release of pressure, which is of great significance to engineering practice.

Measurement and Characteristics Analysis of In Situ Stress in Expanding Area of Tao’er Coal Mine

2011 ◽  
Vol 90-93 ◽  
pp. 1732-1735
Author(s):  
Hu Jun He ◽  
Li Hui Sun ◽  
Sheng Rui Su ◽  
Shu Gang Wang ◽  
Ben Sheng Yang
Keyword(s):  
Coal Mine ◽  
Tectonic Stress ◽  
In Situ Stress ◽  
Parameters Optimization ◽  
Test Results ◽  
Support Design ◽  
Characteristics Analysis ◽  
Roadway Support ◽  
The Stability

In order to fully understand and correctly evaluate the stability of overlying strata and surrounding rock, in-situ stress of south main roadway, north main roadway and bypass in shaft station of expanding area, Tao’er coal mine was tested by KX-81-style triaxial stress gauge of hollow inclusion. The test results show that tectonic stress is main in in-situ stress of expanding area, Tao’er coal mine, horizontal principal stress is westeast distribution, 31.13-27.42MPa size, 27.42°-275° direction. Each stress state is not identical, vertical stress is basically slightly less than the weight of the rock covering on unit area. Application of measuring principle of in-situ stress and analysis of field measurement provide a reliable basis for roadway support design and parameters optimization in expanding area of Tao’er coal mine, ensure safety and smooth construction of roadway.

scholarly journals Impact of the Mining Dimensions on the Stability of Backfilled Pier-Columns

2021 ◽  
Vol 11 (20) ◽  
pp. 9640
Author(s):  
Jianlin Xie ◽  
Weibing Zhu ◽  
Jialin Xu ◽  
Xiaozhen Wang ◽  
Limin Wang
Keyword(s):  
Physical Simulation ◽  
Three Dimensional ◽  
Field Testing ◽  
Mining Areas ◽  
Working Face ◽  
Physical Experiments ◽  
Mining Width ◽  
The Stability ◽  
The Impact

Owing to alternate mining of the new and old mining areas on sites, the mining thickness and width of the working face for pier-column backfilling varies. Thus, there is an urgent need to determine the impact on the bearing performance of the backfilled pier-column after changing the mined dimensions. This study consisted of three-dimensional numerical simulations, physical experiments, and field testing. These methods were performed to study the impact on the stability of the backfilled pier-column after changing the dimensions of the working face. The numerical and physical simulation results revealed that the mining thickness has a greater impact on the stability of the backfilled pier-columns than the width. Field testing results proved that the designed parameters for the backfilled pier-column in situ satisfy the bearing requirements; thus, it can effectively support the overlying strata of the goaf after mining. When increasing the mining thickness, the stress borne by the pier-column increased, and its stability decreased. Upon increasing the mining width, the variation in the stress exerted onto the pier-column was remarkably small, and the change of the elastoplastic zone of the pier-column was also minimal.

scholarly journals Study on the Retention of Large Mining Height and Small Coal Pillar under Thick and Hard Roof of Bayangaole Coal

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Shankun Zhao ◽  
Jianping Zuo ◽  
Lei Liu ◽  
Kaijun Wu
Keyword(s):  
Coal Pillar ◽  
Peak Stress ◽  
In Situ Stress ◽  
Economic Benefits ◽  
Hard Roof ◽  
Working Face ◽  
Large Mining Height ◽  
The Impact ◽  
The Relationship

The coal pillar stress distribution at the 311102 working face in the Bayangaole Mine is analyzed and revealed. In addition, borehole stressmeter, PASSAT monitoring system, and numerical modelling are fully utilized. Based on the patterns of acoustic wave velocity distribution, it is discovered that the impact created by mining activity can expand into the working face around 40 m, where the peak stress concentration is found about 15 m ahead. According to borehole stressmeter readings, mildly impacted, ordinarily impacted, and severely impacted zones are distinguished. The equilibrium theory and corresponding calculation indicated that the coal body in front of the working face has a plastic zone width of 4.96 m. The stress-displacement analysis based on numerical simulation showed that the relationship between peak vertical stress and pillar width is unimodal and bimodal. Specifically, both 5 and 10 m wide pillars showed a unimodal stress-width correlation and the peak vertical stresses are all located at the pillar center, whereas 15 m wide pillar has a bimodal stress-width relationship. In comparison, 10 m wide pillar holds the maximum in-situ stress. In consideration of site conditions and economic influences, 6 m wide coal strip coal pillar is designed at the working face 311102. As a result, stopping was successfully completed, and remarkable economic benefits were achieved.

Study on Excavation Procedure of Dawangou Shallow Tunnel under Unsymmetrical Pressure

2013 ◽  
Vol 353-356 ◽  
pp. 1539-1542
Author(s):  
Su Chao Xu ◽  
T. Y. Liu ◽  
C.Y. Jin
Keyword(s):  
Rock Mass ◽  
In Situ Stress ◽  
Comprehensive Analysis ◽  
Surrounding Rock ◽  
Shallow Tunnel ◽  
Mechanical Index ◽  
Plastic Zones ◽  
Simulation Results ◽  
The Stability

The performance of a tunnel is influenced by such factors as the size and shape of the opening, the in-situ stress and the deformation field and also properties of the rock mass. Different excavation procedures have great important influence on the stability of the surrounding rock, especially for tunnels under unsymmetrical pressure. In this paper, flac3D is used in the simulation of different excavation sequence for Dawanggou tunnel in order to analyze the variation of plastic zones and deformation of the surrounding rock. The numerical results indicate that the mechanical index is different due to variant excavation plans and an optimized plan is determined based on the comprehensive analysis of the index gained from the simulation results.

The Stress Distribution and Calculation of the Different Zone of Wellbore Surrounding Rock Based on the Damaged Theory

2012 ◽  
Vol 170-173 ◽  
pp. 1052-1055
Author(s):  
Wan Chun Zhao ◽  
Chen Yan Sun ◽  
Ting Ting Wang ◽  
Yu Liu ◽  
Cai Ping Yang
Keyword(s):  
Stress Distribution ◽  
Stress Field ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
Oil Well ◽  
Damage Area ◽  
Stress Direction ◽  
The Stability ◽  
Adjacent Rock

In order to describe the stability of borehole face and the theory of hydraulic fracture fissure stretch in real, the stress field of adjacent rock in the hole should be constituted exactly .The article is based on the damnification dynamics theory, meanwhile, considered the rock is fracture-pore dual medium and the damnification characteristic of the rock in hole .Adjacent formation is sectioned three areas: damage-area, damnification-area, elasticity-area. And we have calculated the ambient stress distribution of one oil-well .The results show that the destructive radius of the minimum in-situ stress direction is 1.247m, the damage radius is 8.082m, the destructive radius of the maximum in-situ stress direction is 0.998m, and the damage radius is 6.5865m.

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