An innovative approach to theoretical analysis of partitioned width &amp; stability of strip pillar in strip mining

Wang, Rui; Bai, Jianbiao; Yan, Shuai; Chang, Zhiguo; Wang, Xiangyu

doi:10.1016/j.ijrmms.2020.104301

Cited by 28 publications

(12 citation statements)

References 35 publications

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“…(1) The roadway is equivalent circular (2) The rock mass is characterised as isotropic, continuous, infinite, and initially elastic, and its mechanical properties obey the GZZ strength criterion As shown in Figure 2, the excavation radius of the equivalent circular roadway is R 0 . Here, the hydrostatic stress field σ 0 is applied to the whole area before excavation.…”

Section: Description Of Problemmentioning

confidence: 99%

“…The prediction of rock mass deformation behavior is very useful for deep coal mining [1]. At great depth with strong deep structural activity or high deformability, rock squeezing may occur, and the repair rate of large deformed roadways can reach 70% [2,3]. In the deep coal mining, due to the influences of "three high and one disturbance" (high geo-stress, high ground temperature, high permeable pressure, and the disturbance of mining activities), the unique stress characteristic and plastic yielding were engendered by the mechanics of roadway [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

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The Elastoplastic Solutions of Deep Buried Roadway Based on the Generalized 3D Hoek-Brown Strength Criterion considering Strain-Softening Properties

et al. 2021

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The deep underground roadways are widely used in the mining industries at present, but the relevant theoretical bases are not fully understood. In this paper, the numerical solutions for strain-softening surrounding rock under the generalized three-dimensional (3D) Hoek-Brown (GZZ) strength criterion are developed incorporating the confinement-dependent characteristics of ψ and η ∗ and their influences on the stress and displacement of equivalent circular roadway. On the basic of a finite difference, method for the strain-softening model is proposed to consider the variation of ψ and η ∗ in analyzing the strain-softening behavior of rock masses. Combining the equilibrium equation and strength criterion, the stress conditions for each annulus are calculated analytically. The displacement for each step is obtained analytically by solving the differential equation through invoking flow rule and Hooke’s law. The accuracy of the proposed method is verified through the comparison between the results and the previous studies. The effect of intermediate principal stress of GZZ strength criterion is considered; the rationality of the proposed method is verified by two aspects. First, by comparing with the two-dimensional narrow and generalized H-B strength criterion, the advantage of GZZ strength criterion that considers the effect intermediate main stress is highlighted. On the other hand, compared with the three-dimensional linear D-P criterion, the advantage of GZZ strength criterion in the theoretical research of deep underground roadway in coal mine is highlighted. The results show that the strain-softening of the surrounding rock in the plastic zone of the roadway can reduce the pressure of the surrounding rock, but it will greatly increase its deformation. In the high field stress areas, the strain-softening of surrounding rock is the key reason for the destruction of the roadway. It is suggested that in the design and calculation of the support system of the roadway, the strain-softening characteristics of the surrounding rock should be considered, which is very important to avoid large deformation and damage of roadway.

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Section: Description Of Problemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Elastoplastic Solutions of Deep Buried Roadway Based on the Generalized 3D Hoek-Brown Strength Criterion considering Strain-Softening Properties

et al. 2021

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“…Finally, for the acquisition of action factors, considering that most coal mines are now fully mechanized, instead of the original style, the structure of the coal seam is disturbed very little. Therefore, the minimum value of 1.5 d is the mining influence factor [1].…”

Section: Establishment and Solution Of Water Pressure Failurementioning

confidence: 99%

“…Due to its effective control of surface subsidence, the strip mining method is one of the most commonly used mining methods in 'three-body' coal mining [1]. Therefore, strip mining is widely used at coal mines in China.…”

Section: Introductionmentioning

confidence: 99%

Structure Partition and Reasonable Width Determination of Waterproof Coal Pillar in Strip Mining

et al. 2021

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Retaining a waterproof coal pillar is the most effective water conservation method for a roadway close to the gob, and determining a reasonable width of the waterproof coal pillar has been a common problem among mining scholars for a considerably long time. Based on the mining of the 15208 mining face in Xinjing Coal Mine, the structure of waterproof coal pillar is divided into a mine-pressure-influenced plastic zone, an effective waterproof elastic core zone, and a water pressure failure zone. The mine-pressure-influenced plastic zone width is determined by using the limit equilibrium theory, the parabolic strength theory, and the separation variable method. The effective waterproof elastic core zone width is determined by the semi-inverse solution method, and the water pressure failure zone width is determined by considering the infiltration and softening of water. After that, combined with the previous theoretical analysis of engineering examples, the theoretical value of waterproof coal pillar width is obtained. In addition, the physical shape distribution of the waterproof coal pillar is measured by ultrasonic detection technology. The results are consistent with the field measured results. The correctness of the model is verified. Finally, the rationality of the model is verified by comparing with the previous classical models. The research results are applied to the design of the waterproof coal pillar in Xinjing Coal Mine, which could provide a theoretical basis for determining the width of the waterproof coal pillar located close to a gob.

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“…Several rock bolts can create a reinforced zone to improve the self-supporting capacity of the rock mass [9,10]. Currently, mining depths for both metal ore and coal have increased beyond 1000 m throughout the world, including mines in Sweden, Canada, Australia, and South Africa [11]. Certain metal mines even reached depths greater than 3000 m [12,13].…”

Section: Introductionmentioning

confidence: 99%

An Improved Numerical Simulation Approach for the Failure of Rock Bolts Subjected to Tensile Load in Deep Roadway

et al. 2020

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Our goal was to develop an effective research tool for roadways with significant deformations supported by rock bolts. The improved numerical simulation approach is constructed through additional development of FLAC3D. The aim is to modify the shortcoming that the original model in FLAC3D regards the plastic tensile strain of any arbitrary rock bolt element node as the rupture discrimination criterion. The FISH programming language is adopted to conduct the secondary development and to embed the revised model into the main program of FLAC3D. Taking an actual mining roadway as the simulation object, two simulation schemes adopting the newly improved approach and the original method were conducted, respectively. The results show that (1) the PILE element that constitutes the rock bolt-free section with the maximum elongation rate ruptures after modification, while the rock bolt tendon elongation rate reaches beyond the predefined tensile rupture elongation rate; (2) the modified model in which the rock bolt is mainly subjected to tension realises the tensile rupture phenomenon at the end of the rock bolt-free section and the rock bolt at the junction between the free section and the anchoring section; and (3) only four rock bolts that are in the roadway sides showed rupture in the modified model, and all rock bolts showed rupture in the original model. The tensile failure of the rock bolt led that the modified model scheme is closer to the actual. Compared with the modified model, in the original model, deformation of the surrounding rock masses is severe. This is resulted by the rupture of all rock bolts in the original model. The analysis shows that the improved numerical simulation approach is much more reliable for large deformation roadway behavior with rock bolt support.

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An innovative approach to theoretical analysis of partitioned width & stability of strip pillar in strip mining

Cited by 28 publications

References 35 publications

The Elastoplastic Solutions of Deep Buried Roadway Based on the Generalized 3D Hoek-Brown Strength Criterion considering Strain-Softening Properties

The Elastoplastic Solutions of Deep Buried Roadway Based on the Generalized 3D Hoek-Brown Strength Criterion considering Strain-Softening Properties

Structure Partition and Reasonable Width Determination of Waterproof Coal Pillar in Strip Mining

An Improved Numerical Simulation Approach for the Failure of Rock Bolts Subjected to Tensile Load in Deep Roadway

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