Effect of overburden bending deformation and alluvium mechanical parameters on surface subsidence due to longwall mining

Guo, Wei; Zhao, Guohao; Bai, Erhu; Guo, Mingjie; Wang, Yan

doi:10.1007/s10064-020-02091-4

Cited by 33 publications

(13 citation statements)

References 30 publications

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“…Theoretical Calculation. According to the standard for exploration and evaluation of hydrogeology, engineering geology, and environmental geology of coal deposits (MT/ T1091-2008), the height of the water-conducting fractured zone can be determined as follows [29][30][31]:…”

Section: Evolution Characteristics Of the Water-mentioning

confidence: 99%

Study on Layered-Backfill-Based Water Protection Technology of Thick Coal Seam in the Ecologically Fragile Mining Area in Western China

Zhu

Song

et al. 2022

Geofluids

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The mining areas in Western China are characterized by water shortage and ecological fragility, and the coal resources in these areas are extracted in a large-scale and highly intensive manner, which is highly likely to induce ecological problems, such as soil erosion and grassland degradation. In addition, there is a secondary protection zone of Hongshixia water source near Guojiatan minefield. If the water resources loss of Salawusu Formation is too large, it will affect the normal water supply of Yulin city. To reasonably coordinate coal exploitation and water protection, the development characteristics of water-conducted fissures with different backfill ratios are obtained in combination with theoretical analysis, field test, and numerical modelling. The panel layout of the layered-backfill-based water protection working face and the parallel operation of mining and backfilling are designed, and a feedback regulation system integrating hydrological monitoring and backfill ratios is established, which assists in evaluating the effectiveness of water protection. The results indicated that when the slicing mining method was adopted with the roof naturally caving, the maximum development height of the water conducted fracture zone was 220.0 m (developed to the Yan’an Formation), and the water conducted fracture zone could only develop to the Yan’an Formation without crossing the Zhiluo Formation when the backfill ratio reached 80%. The water emission rates in the west of the field testing area reduced from 334.95 m3/h to 60.60 m3/h, dropping by 86.86%. Compared to the scene prior to the layered backfill mining, the shallow water outflow was reduced by 72.74 m3/h, and it helped annually reduce the shallow water loss of 637200 m3, which was equivalent to 1.74% of the actual water supply to Yunli city every year. The results of this study can provide guidance on effectively avoiding the loss of shallow water resources that are regarded as indispensable sources of domestic water.

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Section: Evolution Characteristics Of the Water-mentioning

confidence: 99%

Study on Layered-Backfill-Based Water Protection Technology of Thick Coal Seam in the Ecologically Fragile Mining Area in Western China

Zhu

Song

et al. 2022

Geofluids

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“…Based on ground pressure theory and the field pressure result, the strata movement law of roof could be summarized as follows: ① for the bedrock with thickness greater than 53.5 m, it has the characteristics of high bearing performance capacity and can form a relatively stable balance of roof structure; thus, the roof subsidence is small and stable. ② For the bedrock with thickness less than 53.5 m, due to the small thickness and low bearing performance of bedrock, the bedrock will slip and become unstable [23], leading to the roof producing large vertical displacement in a short time, further resulting in strong ground pressure such as roof cutting and support crushing on-site [24][25][26][27].…”

Section: Strata Movement Law At Various Bedrock Icknessmentioning

confidence: 99%

Ground Behaviors Analysis of a Stope Covered by the Thin Bedrock and Large-Thick Alluvium: A Case Study

Xiao-ping

Zhang

Tao

et al. 2022

Shock and Vibration

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Support crushing and roof fall accidents frequently occur in the large mining height stope covered by the thin bedrock and large-thick alluvium (TBLA). A comprehensive method including field monitoring, numerical modelling, and theory analysis was performed to investigate the strata movement and its induced ground behaviors of a deep-buried stope under TBLA. The filed measurement results indicated that strong roof periodic weighting phenomenon occurred regularly at an interval of 18–23 m during panel 3301 retreating. During weighting period, dynamic characteristics of hydraulic supports are prominent and characterized by high safety valve opening rate and poor working conditions including tilt down operation and excessive end distance. Additionally, numerical modelling results revealed that the thickness of bedrock affects the movement behaviors of the roof strata and its generated spatial structure significantly. Based on the above results, an integrated control measure was proposed and successfully applied to the test site.

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“…The hard stratum was bent under the overburden load. However, due to the limited separation space, the hard stratum and the strata borne thereby directly acted on the underlying strata, while the underlying strata provided the supporting force, thus limiting the bending deformation of the hard stratum [30,31].…”

Section: Establishment Of the Analysis Model For Overburden Deformati...mentioning

confidence: 99%

“…The critical load and the ultimate displacement in the z direction in different support states can be calculated using Equations ( 20), (30) and (31). The critical load Q1 under the condition is Because the backfill body supports the roof behind the working face during backfill mining, the overburden can be regarded as always supported at two ends in the whole advance process of the working face.…”

Section: Critical Load and Ultimate Displacement Of Hard Stratamentioning

confidence: 99%

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Research on Overburden Failure Characteristics Based on the Theory of Plates and Shells

et al. 2022

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To reveal the overburden failure characteristics during backfill mining, theoretical analysis based on the theory of plates and shells and field measurements were combined. Based on the theory of plates and shells, a mechanical model for the overburden failure mechanism during backfill mining was established, through which the fracture conditions of overburden during backfill mining were judged. By analyzing the fracture process and revealing the fracture mechanism, the fractured zone in overburden during backfill mining was found not to develop uniformly, but changed in a leaping manner. Field measurement was conducted taking the 1327 working face in Xima Coal Mine (Shenyang City, Liaoning Province, China) as an example to monitor and analyze the roof-to-floor convergence (RFC), strata behaviors at the working face, and overburden failure during backfill mining. Monitoring results show that the distance between the monitoring points and the working face was highly consistent with the periodic weighting interval when the RFC increased in a leaping manner; the RFC grew in a leaping manner after each roof weighting, as well as the fractured zone. By monitoring and analyzing overburden failure, it was determined that the maximum height of the fractured zone was 10.7 m and a leaping phenomenon was present in the development process of the fractured zone. The conclusions of theoretical analysis were completely consistent with those of the field measurements, thus confirming the leaping development of the fractured zone in overburden during backfill mining.

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Effect of overburden bending deformation and alluvium mechanical parameters on surface subsidence due to longwall mining

Cited by 33 publications

References 30 publications

Study on Layered-Backfill-Based Water Protection Technology of Thick Coal Seam in the Ecologically Fragile Mining Area in Western China

Study on Layered-Backfill-Based Water Protection Technology of Thick Coal Seam in the Ecologically Fragile Mining Area in Western China

Ground Behaviors Analysis of a Stope Covered by the Thin Bedrock and Large-Thick Alluvium: A Case Study

Research on Overburden Failure Characteristics Based on the Theory of Plates and Shells

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