Numerical modeling for longwall pillar design: a case study from a typical longwall panel in China

Zhang, Guangchao; Liang, Saijiang; Tan, Yunliang; Xie, Fuxing; Chen, Shaojie; Jia, Hong-guo

doi:10.1088/1742-2140/aa9ca4

Cited by 69 publications

(34 citation statements)

References 22 publications

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“…Coal resources account for 70% and 60% of the primary energy production and consumption structure, respectively, and they have always been the main energy source of China. In recent years, the mining scale and intensity of coal mines have gradually increased with the prosperity of coal production each year, and many large and super‐large section chambers and chamber groups have emerged . The cluster distribution of super‐large section chambers makes the interaction between the chambers fierce, and it is very easy to cause dynamic accidents such as roof fall and rib spalling.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of failure evolution for the surrounding rock of a super‐large section chamber group in a deep coal mine

Tan

Fan

Liu

et al. 2019

Energy Science & Engineering

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The stability control of surrounding rock for a large or super‐large section chamber group is a difficult technical problem in deep mining conditions, and this stability control has become one of the most important factors restricting the safety of a large‐scale coal mine. Based on the in‐site geological conditions of a super‐large section chamber group that functions for a coal gangues separation system in the Longgu Coal Mine, we first researched the stress, deformation, and failure characteristics of the in‐site chamber group surrounding rocks by using the FLAC3D software. Simulation results showed that the maximum vertical stress, deformation, and failure range of the surrounding rock for a super‐large section chamber group are larger than those of an ordinary section chamber. In addition, the roof subsidence and the plastic zone radius at the intersection are obviously larger than that of other parts, which increase by approximately 50.8% and 44.4%, respectively. Therefore, the chamber group intersection should be taken as the key area for surrounding rock control. Then, the influences of two key parameters of the chamber group, spacing and angle, were researched in detail to help in the design of the chamber group. Results show that when the chamber spacing is 80 m, the interaction begins to occur. When the angle is 70°, the stress of the surrounding rock and roof subsidence reach the minimum. Thus, the optimum chamber group parameters are determined to be a spacing of 80 m and an angle of 70°. Finally, from the perspective of chamber group stability, the optimal chamber group parameters can better meet the normal use for the super‐large section chamber group. This research provides a reference for the design of a super‐large section chamber group under the same or similar conditions and provides a strategy for controlling the surrounding rock.

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Section: Introductionmentioning

confidence: 99%

Numerical investigation of failure evolution for the surrounding rock of a super‐large section chamber group in a deep coal mine

Tan

Fan

Liu

et al. 2019

Energy Science & Engineering

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“…In addition, few trial model tests have been carried out and the mechanical parameters were adjusted in reference to the in situ measurement of the displacement and the width of yield zones developed around the roadways [23]. The final rock strata property parameters in the numerical model are shown in Tables 2 and 3 The RBB width plays an important role in the convergence of surrounding rock in the GER, as shown in Figure 9.…”

Section: Numerical Modelmentioning

confidence: 99%

Key Parameters of Gob-Side Entry Retaining in A Gassy and Thin Coal Seam with Hard Roof

et al. 2018

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Gob-side entry retaining (GER) employed in a thin coal seam (TCS) can increase economic benefits and coal recovery, as well as mitigate gas concentration in the gob. In accordance with the caving style of a limestone roof, the gas concentration and air pressure in the gob were analyzed, and a roof-cutting mechanical model of GER with a roadside backfill body (RBB) was proposed, to determine the key parameters of the GER-TCS, including the roof-cutting resistance and the width of the RBB. The results show that if the immediate roof height is greater than the seam height, the roof-cutting resistance and width of the RBB should meet the requirement of the immediate roof being totally cut along the gob, for which the optimal roof-cutting resistance and width of RBB were determined by analytical and numerical methods. The greater the RBB width, the greater its roof-cutting resistance. The relationship between the supporting strength of the RBB and the width of the RBB can be derived as a composite curve. The floor heave of GER increases with increasing RBB width. When the width of the RBB increased from 0.8 m to 1.2 m, the floor heave increased two-fold to 146.2 mm. GER was applied in a TCS with a limestone roof of 5 m thickness; the field-measured data verified the conclusions of the numerical model.

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“…By using the overlap reduction technique, Van introduced an alternative formula for the calculation of coal pillar strength, and through direct strength tests of coal pillars of different sizes, Bieniawski obtained a formula for coal pillar strength. The above formulae assume that the loading distribution on a coal pillar is uniform; however, this is typically not the case …”

Section: Introductionmentioning

confidence: 99%

Field and numerical investigations of gateroad system failure under an irregular residual coal pillar in close‐distance coal seams

Shang

Ning

et al. 2019

Energy Science & Engineering

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The Gaojialiang Coal Mine in Inner Mongolia in China was used as an example to investigate the process of chain pillar and gateroad failure in the lower coal seam under the effect of an irregular residual coal pillar in the upper close‐distance coal seam. The results indicated that after the longwall face in the lower coal seam retreated through the area under the large irregular residual coal pillar in the upper coal seam, the bearing area of the residual coal pillar decreased and the roof pressure continuously concentrated in the elastic core area of the residual coal pillar. Isolated triangular slab rock was formed above the triangular residual coal pillar, and the weight of the overlying strata was transferred downward through the triangular slab rock. When the chain pillar under the residual coal pillar was destroyed due to loading that exceeded its carrying capacity, the upper triangular slab rock rotated and sank, which resulted in the intensification of the concentrated stress in the solid rib of the gateroad in the lower coal seam. Based on the analysis, it is suggested that in the design of a longwall system, a gateroad under an isolated residual coal pillar in the upper coal seam should be avoided when mining in close‐distance coal seams.

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Numerical modeling for longwall pillar design: a case study from a typical longwall panel in China

Cited by 69 publications

References 22 publications

Numerical investigation of failure evolution for the surrounding rock of a super‐large section chamber group in a deep coal mine

Numerical investigation of failure evolution for the surrounding rock of a super‐large section chamber group in a deep coal mine

Key Parameters of Gob-Side Entry Retaining in A Gassy and Thin Coal Seam with Hard Roof

Field and numerical investigations of gateroad system failure under an irregular residual coal pillar in close‐distance coal seams

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