Failure Process of Rock Strata Due to Multi-seam Coal Mining: Insights from Physical Modelling

Qin, Yan; Xu, Nengxiong; Zhang, Zhongjian; Zhang, Bin

doi:10.1007/s00603-021-02415-0

Cited by 23 publications

(13 citation statements)

References 30 publications

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“…On this basis, we establish a physical model to conduct a physical simulation test 35 , 36 , and the deformation mechanism of the overlying strata in the mined-out area of the Lanhe Coal Mine is analysed.…”

Section: Methodsmentioning

confidence: 99%

“…In the study of the mechanism of geological disasters in mined-out areas, indoor experiments, numerical simulations, on-site monitoring and other methods have been used 22 – 31 . During indoor testing for investigating mined-out areas, similar materials have been selected for layered masonry simulation of different strata, mainly studying the deformation characteristics of the overlying rock in mined-out areas, with less consideration given to the deformation of loose layers 22 , 24 , 25 , 27 , 30 . In numerical simulation of mined-out areas, the discrete element method has often been employed, but the simulation results are greatly influenced by the calculation model and rock mechanics parameters 23 – 25 .…”

Section: Introductionmentioning

confidence: 99%

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Deformation characteristics of overlying strata in room and pillar mined-out areas under coal pillar instability

Liu,

Gu,

Wang

et al. 2024

Sci Rep

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Under the condition of small roof deformation before the occurrence of fractures and collapse in room and pillar mined-out areas caused by coal pillar instability, the surface deformation may be large, which threatens the safety of ground structures. Interferometric synthetic aperture radar, geophysical exploration, geotechnical exploration and physical simulation tests were conducted to analyse the deformation and development mechanism of the overlying strata in the mined-out area in this case. The results show that in terms of surface deformation, the surface deformation caused by coal pillar instability in the room and pillar mined-out area exhibits the slow deformation stage, uniform deformation stage and accelerated deformation stage. In terms of deformation of overlying strata, after the completion of room and pillar mining, a strip-shaped deformation area and trapezoidal deformation area are developed in the overlying rock. With the occurrence of coal pillar instability, a trapezoidal deformation area and inverted funnel-shaped deformation area are developed in the overlying rock. The deformation characteristics of unconsolidated formations transition from trapezoidal deformation after room and pillar mining to funnel-shaped deformation due to coal pillar instability. Moreover, the maximum surface deformation point is located at the centre of the funnel. In terms of spatial morphology of mined-out area deformation, the maximum surface deformation point corresponds to the position of the initial coal pillar instability and the crack in the mined-out area roof along the vertical direction. The mined-out area treatment method can be optimized based on the deformation characteristics of the overlying strata in the room and pillar mined-out area under the condition of coal pillar instability.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Deformation characteristics of overlying strata in room and pillar mined-out areas under coal pillar instability

Liu,

Gu,

Wang

et al. 2024

Sci Rep

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“…Physical modelling experiments have been widely utilized to study strata movement over coal mining to represent field-scale scenarios 12 , 35 – 38 . In this study, we conducted the physical modelling experiment on the physical modelling experimental platform specified for studying underground coal mining with multiple coal seams developed by the State Key Laboratory of Water Resources Protection and Utilization in Coal Mining.…”

Section: Physical Modelling Experimentsmentioning

confidence: 99%

“…However, these studies commonly involved complex geological and geomechanical conditions, which made it difficult to fully illuminate the underlying mechanism since the strata were hardly visible 16 . On the other hand, down-scale physical modelling in the laboratory have been extensively leveraged to disclose the development of cracks/fractures and the overlying strata deformation/movement over the advancement of the working face 12 , 35 – 38 , mainly due to the advantages of visualization and effective analogy. Most studies of physical modelling experiments have been conducted emphasizing the overlying strata movement during the mining of a single coal seam 11 , 12 .…”

Section: Introductionmentioning

confidence: 99%

On strata damage and stress disturbance induced by coal mining based on physical similarity simulation experiments

Yang,

Li,

Wang

et al. 2023

Sci Rep

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Extensive studies have been conducted on the movement of overlying strata when a single coal seam is mined. However, structural characteristics and associated stress field variation of the overlying strata over multiple coal seam mining remain unclear. Here we performed physical modelling experiments analogous to No. 42108 working face of Buertai coal mine, Shendong coalfield, where No. 22 coal seam (2.9 m thickness) was mined first, preceding No. 42 upper coal seam (6.1 m thickness) with an inter-coal-seam distance of 72.8 m. We employed DIC (digital image correlation) measurement and systematically-laid pressure cells to visualize the overlying strata movement and monitor stress field variations over multiple coal seam mining. We found that the stress of the inter-coal-seam strata increased significantly in the late mining stage of No. 22 coal seam due to the strata collapse, and culminated after compaction of the caved blocks. The inter-coal-seam strata stress gradually decreased over mining of No. 42 upper coal seam and arrived at zero after the inter-coal-seam strata collapsed. The mining of No. 42 upper coal seam aggravated the roof settlement of No. 22 coal seam; and the floor stress was noticeably lower than that of No. 22 coal seam due to the pressure-relief caused by the former mining activity. Our physical modelling findings advanced our understanding on structural characteristics and stress evolutions of overlying strata over multiple coal seam mining and offered guidance for prediction and mitigation of strata movement associated disasters in underground coal mining with geomechanical and mining conditions similar to those of Buertai coal mine.

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“…The stress field distribution of bedrock and surface needs to be further discussed. Qin [8], Dong [9], Yang [10], and others used a combination of various methods to study the structural characteristics of mining MCS and analyzed roof instability and working face pressure, the calculation method of coal mine support resistance and the breaking impact effect of roof structure, and obtained the laws of MCS bedrock failure and roof structure characteristics. Based on the study of coal seam group, the stability and rock failure mechanical characteristics are analyzed.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on Characteristics of Bedrock and Surface Failure in Mining of Shallow-Buried MCS

2022

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Coal is one of the important energy sources for industry. When it is mined, it will cause the destruction of bedrock and surface. However, it is more severe in mining shallow-buried multi coal seams (SBMCS). To better reveal the characteristics of the bedrock and surface damage, we have carried out a theoretical analysis, as well as used numerical simulations and field monitoring methods to study the surface and bedrock damage caused by the mining of SBMCS. The characteristics of bedrock and surface failure structure, settlement, and stress distribution were studied and analyzed. The findings show that the collapsed block, formed by the rupture of the overlying stratum, interacts with the surrounding rock to form large cavities and gaps, and the stress concentration occurs between them. The maximum downward vertical concentration stress is about 9.79 MPa. The mining of the lower coal seam can lead to repeated failure of the upper bedrock and goaf. The settlement of bedrock presents gradient change, and the settlement of upper bedrock is large, about 8.0 m, and the maximum settlement is 8.183 m, while that of lower bedrock is small and about 3.5–4.0 m. The weak rock stratum in the bedrock is crushed by the change stress of repeated mining, and formed a broken rock stratum. The cracks in the bedrock develop directly to the ground. On the ground, tensile cracks, compression uplift, stepped cracks, and even collapse pits are easy to cause in mining SBMCS. Affected by repeated mining, the variation of surface vertical stress is complex and disorderly in the middle of the basin, and the variation of horizontal stress is mainly concentrated on the edge of the basin. The maximum stress reaches 100 KPa, and the minimum stress is about 78 KPa. Through theoretical analysis and discussion, the size of the key blocks is directly related to the thickness and strength of the rock stratum.

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Failure Process of Rock Strata Due to Multi-seam Coal Mining: Insights from Physical Modelling

Cited by 23 publications

References 30 publications

Deformation characteristics of overlying strata in room and pillar mined-out areas under coal pillar instability

Deformation characteristics of overlying strata in room and pillar mined-out areas under coal pillar instability

On strata damage and stress disturbance induced by coal mining based on physical similarity simulation experiments

Numerical Study on Characteristics of Bedrock and Surface Failure in Mining of Shallow-Buried MCS

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