Numerical Analysis of Influencing Factors of Stability in Thick Coal Seam Mining Roadway

2012 ◽  
Vol 256-259 ◽  
pp. 1453-1457
Author(s):  
Zhi Hua Li ◽  
Xin Zhu Hua ◽  
Ke Yang ◽  
Ruo Jun Zhu ◽  
De Sheng Zhou

The FLAC-3D software was used to study the surrounding rock displacement and the side abutment pressure distribution laws about roadway in thick coal seam. Based on this model, through change the mining height, working face length and mining depth, the differences of roadway underground pressure characteristics were analyzed between thick coal seam working face and normal working face. The results indicate that: ①the displacement of roadway surrounding rock increases with the increase of mining depth and mining height, the closer to the coal wall the larger of the increase range of roadway displacement. ②the peak of side abutment pressure increases with the increase of mining depth and mining height, the peak district of the stress will move toward the inner department of rock body. ③ the effect of working face length on the roadway displacement and the side abutment pressure is very feeble.

2013 ◽  
Vol 634-638 ◽  
pp. 3428-3432 ◽  
Author(s):  
Zhi Hua Li ◽  
Xin Zhu Hua ◽  
Ruo Jun Zhu ◽  
De Sheng Zhou

In order to study the strata behavior characteristics in super-long and large mining height working face, the FLAC-3D software was used to study the roof displacement and the abutment pressure distribution laws of working faces. The results indicate that: ① the influence range is larger of front abutment pressure in Liuzhuang coal mine 171301 super-long large mining height working face, and reaches to 60m. ② the maximum roof displacement increases with the increase of mining depth and working face length, the increase in magnitude decreases gradually, while the maximum roof displacement sharply increases due to the increase of mining height. ③ the peak abutment pressure increases with the increase of mining depth and mining height, the location of peak abutment pressure transfer to ahead of the coal wall. ④ the effect of working face length on abutment pressure is very feeble, so, the strata behavior characteristics remain almost constant with the increase of face length.


Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 188 ◽  
Author(s):  
Wenyu Lv ◽  
Yongping Wu ◽  
Liu Ming ◽  
Jianhui Yin

The artificial-caved rock composited backfilling approach can effectively restrain the dynamic phenomena in the coal seam and the associated roof and floor during mining operations, and can also improve the stability of the system of support and surrounding rock. In this study, based on the analysis of influencing factors affecting the surrounding rock movement and deformation of the composited backfilling longwall face in a steeply dipping coal seam, the roof mechanical model is developed, and the deflection differential equation is derived, to obtain the roof damage structure and the location of the roof fracture for the area without backfilling. The migration law of the roof under different inclination angles, mining depths, working face lengths, and backfilling ratios are analyzed. Finally, mine pressure is detected in the tested working face. Results show that the roof deflection, bending moment, and rotation drop with the increase of the inclination angle and backfilling ratio, whereas these parameters increase with greater mining depth and working face length. The roof failure location moves toward the upper area of the working face as the inclination angle and working face length increases, while it moves toward the center of the non-backfilling area with greater mining depth and backfilling ratio. Results from the proposed mechanical model agree well with the field test results, demonstrating the validity of the model, which can provide theoretical basis for a safe and efficient mining operation in steeply dipping coal seams.


2013 ◽  
Vol 295-298 ◽  
pp. 2980-2984
Author(s):  
Xiang Qian Wang ◽  
Da Fa Yin ◽  
Zhao Ning Gao ◽  
Qi Feng Zhao

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.


2014 ◽  
Vol 522-524 ◽  
pp. 1386-1389
Author(s):  
Zhong Ping Guo ◽  
Hui Qiang Duan ◽  
Fan Feng ◽  
Gui Yin Zhang

According to the occurrence conditions of deeply inclined coal seam of 81206 working face in Yanya coal mine, methods including transmission rock theory calculation and numerical calculation based on the relationship between supports and surrounding rock are used to calculate and analyze. The proper working resistance of support is 5979.2kN and the supporting intensity is 0.8~0.95MPa. The regression equation associated with roof subsidence displacement , thickness of the coal seam, working face length and supporting intensity is accomplished, which provides theoretical basis for the support selection.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xie Fuxing

The gob-side roadway of 130205, a large-mining-height working face in the Yangchangwan coal mine, was investigated in terms of the mine pressure law and support technology for large mining heights and narrow coal pillars for mining roadways. The research included field investigations, theoretical analysis, numerical simulation, field tests, and other methods. This paper analyzes the form of movement for overlying rock structure in a gob-side entry with a large mining height and summarizes the stress state and deformation failure characteristics of the surrounding rock. The failure mechanism of the surrounding rock of the gob-side roadway and controllable engineering factors causing deformation were analyzed. FLAC3D numerical simulation software was used to explore the influence law of coal pillar width, working face mining height, and mining intensity on the stability of the surrounding rock of the gob-side roadway. Ensuring the integrity of the coal pillar, improving the coordination of the system, and using asymmetric support structures as the core support concept are proposed. A reasonably designed support scheme for the gob-side roadway of the working face for 130205 was conducted, and a desirable engineering effect was obtained through field practice verification.


2011 ◽  
Vol 328-330 ◽  
pp. 1671-1674
Author(s):  
Ying Ma ◽  
Sheng Zhong

Using unified model and theory of rock pressure, the problems, such as caving of stope roof with large mining height and destruction of support, strata movement and surface subsidence, are unified analyzed and researched. The results show that: pressure shell is dynamic shell, which moves forward with the propulsion of working face; with the increase of mining height on the face, the height of fracture zone in coal seam increases, not continuously, but jumpily; with the increase of mining height, support load rises, but the degree of this rise decreases gradually, increased degree of immediate roof weight should be greater than that of given deformation pressure. The results provide necessary basis for reliability of hydraulic support on the working face with large mining height and safety work in the underground.


2021 ◽  
Author(s):  
Luo Shenghu ◽  
tong wang ◽  
Wu Yongping ◽  
Huangfu Jingyu ◽  
Zhao Huatao

Abstract The key to the safe and efficient longwall mining of steeply dipping seams lies in the stability control of the "support-surrounding rock" system. This paper analyzes the difficulty of controlling the stability of the support during the longwall mining process of steeply dipping coal seams in terms of the characteristics of the non-uniform filled-in gob using a combination of physical test, theoretical analysis and field measurements. Considering the floor as an elastic foundation, we built a "support-surrounding rock" mechanical model based on data obtained on "support-surrounding rock" systems in different regions and the laws of support motion under different load conditions. Our findings are summarized as follows. First, depending on the angle of the coal seam, the caving gangue will roll (slide) downward along the incline, resulting in the formation of a non-uniform filling zone in the deep gob in which the lower, middle, and upper sections are filled, half-filled, and empty, respectively. In addition, an inverted triangular hollow surface is formed on the floor of the gob in the middle and upper sections behind the support. Furthermore, as the angle of the coal seam, length of the working face, and mining height increase, the characteristics of the non-uniform filled-in gob are enhanced. Second, we found that, as a result of support by the gangue, the "support-surrounding rock" system is relatively stable in the lower part of the working face while, in the middle and upper sections of the working face, the contact method and loading characteristics of the support are more complicated, making stability control difficult. Third, the magnitude and direction of the load, action point, and mining height all affect the stability of the support to varying degrees, with the tangential load and action position of the roof load having the most significant impacts on the stability of the support. Under loading by the roof, rotation and subsidence of the support inevitably occur, with gradually increasing amplitude and effects on the inter-support and sliding forces. Finally, we found that it is advisable in the process of moving the support to adopt "sliding advance of support" measures and to apply a "down-up" removal order to ensure overall stability. These research results provide reference and guidance of significance to field practice production.


2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Xingen Ma ◽  
Manchao He ◽  
Xuewei Sun ◽  
Jianfeng Li ◽  
Gang He ◽  
...  

Gob-side entry retaining technology with roof cutting (GERRC) has been widely used in flat and near-flat coal seam conditions, but its application under inclined coal seam is still very deficient. In order to further improve the application system of GERRC and overcome the application difficulties under special geological conditions, this paper takes the 43073 working face of Yixin coal mine as an example to research the GERRC with upper roadway under gently inclined thick coal seam. Firstly, the difficulties in the upper entry retaining with inclined coal seam are analyzed and the corresponding key technologies and system designs are put forward. Subsequently, the roof cutting and upper entry retaining are designed in detail according to geological conditions of test working face, and the roof cutting and pressure releasing effect is analyzed by numerical simulation to expound the stress distribution and pressure releasing mechanism of surrounding rock. Finally, the upper entry retaining field test is carried out to verify the feasibility and applicability of the technology and related designs. Through field monitoring, it is found that the weighting step increases significantly, the weighting strength decreases effectively on the roof cutting side, and the pressure relief effect is obvious. Meanwhile, the maximum roof to floor convergence is 361 mm and the maximum shrinkage of both sides is 280 mm, so the retained entry can meet the reuse requirement of adjacent working face.


Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2470 ◽  
Author(s):  
Yiwen Lan ◽  
Rui Gao ◽  
Bin Yu ◽  
Xiangbin Meng

The movements of overburden induced by mining a thick coal seam with a hard roof extend widely. The effects of breakages in the hard strata on the strata behaviors might vary with the overlying strata layers. For this reason, we applied a test method that integrated a borehole TV tester, borehole-based monitoring of strata movement, and monitoring of support resistance for an in situ investigation of a super-thick, 14–20 m coal seam mining in the Datong mining area in China. The results showed that the range of the overburden movement was significantly high, which could reach to more than 300 m. The key strata (KS) in the lower layer main roof were broken into a ‘cantilever beam and voussoir beam’ structure. This structure accounted for the ‘long duration and short duration’ strata behaviors in the working face. On the other hand, the hard KS in the upper layer broke into a ‘high layer structure’. The structural instability induced intensive and wide-ranging strata behaviors that lasted for a long time (two to three days). Support in the working face were over-pressured by large dynamic factors and were widely crushed, while the roadways were violently deformed. Hence, the structure of a thick coal seam with a hard roof after mining will form a ‘cantilever beam and voussoir beam and high layer structure’, which is unique to a large space stope.


2011 ◽  
Vol 217-218 ◽  
pp. 1641-1646
Author(s):  
Nian Jie Ma ◽  
Guo Dong Zhao ◽  
Chun Lei Ju ◽  
Chong Li ◽  
Xiang Zhong Dong

In order to grasp the movement rules of three soft coal caving complex working plane strata and stoping space surrounding rock and hydraulic support interactions relationship, improve the management of mining roof, to do research about the distribution rule of caused abutment pressure and shield support of initial supporting force, the work resistance and adaptability of coal seam. The first coalface of testing mine 1301 mining coal gangue is clip three soft and thick coal seam mining, adopt fully mechanized caving technology, choose ZF6400/17/32 type support screen type top coal caving hydraulic to support working face roof support, in order to provide better services for safe production in the working face, especially study on related factors affecting the observational of working mine pressure.


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