Theoretical Analysis of Damaged Width &amp; Instability Mechanism of Rib Pillar in Open‐Pit Highwall Mining

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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“…In this study, based on the previous studies [46], the ultimate width of the loose zone can be described as follows:…”

Section: Theoretical Analysis Of the Width Of The Waterproof Coal Pillarmentioning

confidence: 99%

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

et al. 2021

Self Cite

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“…Due to the loess and gangue used in the backfilling zone III, the slope reinforcement was limited. Without considering the hydraulic effect and the reinforcement of backfilling zone to the slope foot, the length of the slip surface formed by the width of the pillar and the length of the broken section determine the slope stability [26,27].…”

Section: The Stability Analysis Of the Protective Pillar Of Slopementioning

confidence: 99%

A Study on the Impact of Longwall‐Mining Operation on the Stability of a Slope‐Pillar Structure

Bai

Zhang

Wang

et al. 2021

Shock and Vibration

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The slope-pillar structure is defined as an artificial construction shaped by a surface highwall mining and an underground longwall mining. In order to study the impact of stress variations (induced by the longwall-mining operations) on the stability of a slope-pillar structure, No. 30101-1 working face of Nanliang Coal Mine was selected as the study subject. A series of analysis including physical similar simulation test and the theoretical analysis were conducted to study the movement pattern of the overlying strata in the working face of the slope and the loading and the stability of the pillar column revealing the mechanism of dynamic load instability of nonuniformly distributed load “slope pillar.” A “slope-pillar” reverse sliding structural model was proposed along with a newly established “slope-pillar” structural mechanical model and a formula to calculate the boundary width of the protection for the pillar under the extreme balance conditions. According to the study, the width of the protective pillar is designed at 20 m, and the roadway deformation during the working face and the stability of the pillar can satisfy the safety requirement concerning the working face, which further validates the theoretic deduction formula.

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“…Coal has long been the main energy source in China [1,2]. In view of the exhaustion of shallow resources in recent years, the resource exploitation and space development gradually have been transferred to the deep earth [3,4].…”

Section: Introductionmentioning

confidence: 99%

An Innovative Elastoplastic Analysis for Soft Surrounding Rock considering Supporting Opportunity Based on Drucker‐Prager Strength Criterion

Wang

Bai

et al. 2021

Advances in Civil Engineering

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In order to study the mechanism of excavation and supporting process of equivalent circular roadway, the model of soft roadway was established firstly. The elastoplastic solutions in excavation process were deduced based on Drucker-Prager strength criterion. Then, the elastoplastic solution under supporting condition was obtained based on homogenization method under the condition of rockbolts and liner supporting. Lastly, an example was analyzed to study the effect of different factors such as “space effect,” supporting opportunity, stresses, surrounding displacement, and the radius of plastic zone. Based on theoretical research case, the change rules of considering the “space effect” and the supporting opportunity when calculating the subarea of the roadway were discussed, the control of interval distance of rockbolts on the displacement of surrounding rock mainly reflecting in the plastic residual zone and the “space effect” in excavation, and the supporting time to control the displacement of surrounding rock not being ignored are revealed. The results can provide an important theoretical basis for the stability evaluation and quantitative support design of roadway surrounding rock. Therefore, the “space effect” and the supporting time to control the displacement and stresses of surrounding rock can not being ignored in underground engineering.

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Theoretical Analysis of Damaged Width & Instability Mechanism of Rib Pillar in Open‐Pit Highwall Mining

Cited by 16 publications

References 16 publications

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

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

A Study on the Impact of Longwall‐Mining Operation on the Stability of a Slope‐Pillar Structure

An Innovative Elastoplastic Analysis for Soft Surrounding Rock considering Supporting Opportunity Based on Drucker‐Prager Strength Criterion

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