Stability study on naturally filling body in gob-side entry retaining

Zhou, Biao; Xu, Jing; Zhao, Maosen; Qing-lin, Zeng

doi:10.1016/j.ijmst.2012.01.001

Cited by 26 publications

(16 citation statements)

References 2 publications

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“…Since the retained entry in the zero-pillar mining will experience more dynamic mining disturbances, the entry control techniques appear to be very important. Much research has been conducted on GER applied on thin and medium coal seams regarding the properties and stability of filling bodies [10][11][12], the transfer bearing mechanisms of roofs [13][14][15], and deformation control of retained entries [16][17][18]. Up to now, however, studies of Gob-side entry retaining applied in thick coal seams have rarely seen in the published literatures [19].…”

Section: Introductionmentioning

confidence: 99%

An Innovative Approach for Gob-Side Entry Retaining in Thick Coal Seam Longwall Mining

et al. 2017

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Gob-side entry retaining (GER) is a popular non-pillar mining technique regarding how to reserve a gateroad for the use of next panel mining. When used in thick coal seams, the conventional entry retaining method requires a huge amount of filling materials and may cause entry (gateroad) accidents. Thus, an innovative non-pillar longwall mining approach is introduced. First, structural and mechanical models were built to explore the mechanism of the new approach. The modeling results indicate that effective bulking of the gob roof and reasonable support of the entry roof were key governing factors in improving entry stabilities and reducing roof deformations. Accordingly, a directional roof fracturing technique was proposed to contribute to gob roof caving, and a constant resistance and large deformation anchor (CRLDA) cable was used to stabilize the entry roof. Subsequently, the evolutionary laws of the roof structure and stresses were explored using numerical simulation. It was found that the structure of the surrounding rocks around the retained entry changed significantly after roof fracturing. The stress-bearing center was transferred to the gob area, and the entry roof was in a low stress environment after adopting the approach. Finally, the approach was tested on a thick coal seam longwall mining panel. Field monitoring indicates that the retained entry was in a stable state and the index of the retained entry met the requirement of the next mining panel. This work provides an effective and economical approach to non-pillar longwall mining in thick coal seams.

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Section: Introductionmentioning

confidence: 99%

An Innovative Approach for Gob-Side Entry Retaining in Thick Coal Seam Longwall Mining

et al. 2017

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“…Different widths of filling body bear different compressive stress, and the compressive stress will tend to be stable when the width reaches a certain value (Han et al 2019;Sun et al 2019;Cheng et al 2020). Appropriate strength of filling body can not only relieve roof pressure and strong impact load, but also increase support resistance and prevent filling from being crushed (Kong et al 2021;Ning et al 2014;Zhou et al 2012;Xie et al 2020). Zhang et al (2020b) through uniaxial compression test and AE test, compared the post-peak performance of high water content material samples and concrete samples, and the results showed that the internal damage of high water content material samples was very slow in the post-peak stage, and the damage was much smaller than that of concrete samples.…”

Section: Introductionmentioning

confidence: 99%

Determination of Reasonable Width of Filling Body for Gob-Side Entry Retaining in Mining Face With Large Cutting Height

Pu¹,

Wu²,

Liu³

et al. 2021

Preprint

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When gob-side entry retaining is adopted in mining face with large cutting height, due to large stope space, strong dynamic pressure and other reasons, the filling body is usually broken and unstable due to improper width of filling body, and the stability of surrounding rock of roadway is poor. Therefore, this paper will take Shaqu mine as the engineering background to study the reasonable filling body width of gob-side entry retaining in mining face with large cutting height. Firstly, the stability factors of gob-side entry retaining in mining face with large cutting height are analyzed, and the mechanical model of bearing structure of gob-side entry retaining is established based on the lateral pressure and overlying load of filling body, and the reasonable width of filling body is obtained quantitatively; Numerical simulation is used to analyze the evolution of vertical stress, vertical displacement and plastic zone of working face with the change of filling body width. Finally, combined with the deformation observation results of 24207 gob-side entry retaining roof, two sides and filling body, the rationality of filling body width is verified. The results show that: the setting of the width and strength of the filling body plays an important role in the stability of gob-side entry retaining. According to the mechanical model, the minimum width of the filling body is 2.2m in the lateral direction and 3.9m in the vertical direction; Numerical simulation shows that when the width of filling body is too small, with the increase of filling body width, the vertical stress of filling body increases gradually. When the width of filling body reaches a certain value, the vertical stress decreases with the increase of width, and the stress concentration area will change from symmetrical type to eccentric load type, from the middle of filling body to the side of filling body near gob. If the width of the filling body is too small, the filling body will be too broken to bear the load, resulting in too small vertical stress and too large vertical displacement of the roadway roof. The larger the width of the filling body is, the greater the cutting resistance is, the more timely the side roof of the gob can be cut off, the less the stress of the roadway and the filling body, and the more stable the retained roadway is. Finally, through the observation of 24207 gob-side entry retaining, the total deformation of two sides and roof and floor of roadway tends to be stable after 665mm and 597mm respectively. The roof of roadway does not appear severe subsidence and obvious cracking, and the floor does not appear too large floor heave. The effect of roadway retaining is good, which indicates that 4m support can meet the needs of practical engineering.

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“…It can improve the recovery rate of coal, reduce roadway drivage ratios, extend the service life, and reduce gas accumulation in the upper corner as well as prevent mining disasters caused by the remaining coal pillars [5][6][7][8][9]. However, field engineering demonstrated that it still encounters many difficult problems, such as severe roadway deformation and the slow speed of gob-side entry retaining [10][11][12][13][14]. e severe deformation of roadway does not meet the production requirements, often requiring much cost and time to repair for reusing; moreover, the slow speed of gobside entry retaining is not consistent with the rapid mining and inevitably restricts the efficient production.…”

Section: Introductionmentioning

confidence: 99%

Stability Control and Quick Retaining Technology of Gob‐Side Entry: A Case Study

Luan

Jiang

Zhou

et al. 2018

Advances in Civil Engineering

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In Chinese coal mines, gob-side entry retaining, an efficient technique for coal mining, has been widely used. However, severe roadway deformation and slow retaining speed have gravely restricted the popularization and its application. Hence, in order to solve the existing problems, the deformation mechanism of gob-side entry was studied. Then, a new approach for gob-side entry retaining technique (GERT) was proposed to increase the speed of gob-side entry retaining. Finally, the application effect of the new GERT method was tested and analysed. The results show that the rotation and subsidence of roof key block B lead to severe deformation of roadway. And the proposed gob-side entry stability control technology can affectively resist the severe roadway deformation. Compared with the conventional support method for gob-side entry retaining, GERT has completed the complex wall construction work in advance, thereby simplifying the process of gob-side entry retaining and increasing the speed of gob-side entry retaining. When retaining the entry in panel 183U04 with the new support method, the entry retaining speed significantly improved from 0.25 m/h to 1.0 m/h compared with the traditional method, and then the problem of gob-side entry severe deformation was solved.

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Stability study on naturally filling body in gob-side entry retaining

Cited by 26 publications

References 2 publications

An Innovative Approach for Gob-Side Entry Retaining in Thick Coal Seam Longwall Mining

An Innovative Approach for Gob-Side Entry Retaining in Thick Coal Seam Longwall Mining

Determination of Reasonable Width of Filling Body for Gob-Side Entry Retaining in Mining Face With Large Cutting Height

Stability Control and Quick Retaining Technology of Gob‐Side Entry: A Case Study

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