Research on the overburden deformation and migration law in deep and extra-thick coal seam mining

Sun, Binyang; Zhang, Pingsong; Wu, Rongxin; Fu, Maoru; Ou, Yuanchao

doi:10.1016/j.jappgeo.2021.104337

Cited by 28 publications

(12 citation statements)

References 9 publications

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“…13 . The existing literature has introduced in detail the performance parameters, field construction and test result analysis of optical cables and equipment 10 , 11 , 17 , 18 . Therefore, this part will not discuss the principle, test effect, influencing factors, judgment standards and other related issues of this technology.…”

Section: Discussionmentioning

confidence: 99%

“…The borehole electrical method uses the resistivity value as a parameter to evaluate and analyse the risk of rock deformation and failure or water inrush from the working face 14 – 18 . However, this parameter is unstable, has low accuracy and high interference, and often leads to large jumps and fluctuations in the resistivity value, which impact the final result.…”

Section: Introductionmentioning

confidence: 99%

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Geoelectric field response characteristics analysis of floor roadway surrounding rock fracture caused due to coal seam mining

Zhang

et al. 2021

Sci Rep

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The fracture of rocks surrounding the floor roadway during the mining of the working face of a coal mine is a complicated spatiotemporal process due to the superimposed action of multiple stress fields on the surrounding rock mass. Using the surrounding rock of a floor roadway in the working face of the Huainan Pan’er Mine as the research subject, we conducted real-time monitoring using geoelectric field monitoring technology, and found the spatiotemporal response law of the geoelectric field in the process of regional rupture and damage of engineering rock masses under a complex stress field environment. The results show that (1) the time series response characteristics and spatial distribution of the geoelectric field signal are closely related to the stress distribution and damage evolution of the surrounding rock mass; (2) the rupture and damage degree of the goaf floor significantly increased when the working face was pushed through the monitoring area for 20–40 m. During this process, the excitation current dropped by 4–12 mA, and the self-potential pulse fluctuation amplitude was greater than 400 mV; (3) from the beginning of the monitoring process to the end of the monitoring, the self-potential in the damaged area decreased by 250 mV, and the self-potential in the mudstone layer below the damaged area increased by 140 mV. The electrons released into the environment around the damaged rock mass during the severe impact phase of mining did not flow back to the damaged area, and the positive charge in the damaged rock mass gradually accumulated in the complete rock mass in units of rock strata; (4) when superimposed and supported by anchor rod and cables, the bearing capacity of the shallow bearing circle of the roadway was enhanced, and the excitation current presented a step-like overall increase during mining of the working face with a small drop after every significant increase. This result is of significance in monitoring the evolutionary process of real-time failure of rock masses under complex stress environments using geoelectric field information and in improving the quality of geoelectric field monitoring technology testing applications in the future.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Geoelectric field response characteristics analysis of floor roadway surrounding rock fracture caused due to coal seam mining

Zhang

et al. 2021

Sci Rep

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“…Therefore, to meet the economic needs of China’s sustainable development, mining deeper coal resources will be necessary. The effect of deep mining is completely different from that of shallow mining (Sun et al. , 2021; Zhao et al.…”

Section: Introductionmentioning

confidence: 98%

“…Therefore, to meet the economic needs of China's sustainable development, mining deeper coal resources will be necessary. The effect of deep mining is completely different from that of shallow mining (Sun et al, 2021;Zhao et al, 2021;Zhang et al, 2020). Deep resource mining is a high in situ stress environment, and the weak disturbance process of excavation and mining may induce a large amount of stress concentration, plastic strain and rock strata compression deformation.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis for mining-induced stress and plastic evolution involving influencing factors: high in situ stress, excavation rate and multilayered heterogeneity

Wang

Huang

Wang

2022

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PurposeThis study aims to analyse the deep resource mining that causes high in situ stress, and the disturbance of tunnelling and mining which may induce large stress concentration, plastic deformation and rock strata compression deformation. The depth of deep resources, excavation rate and multilayered heterogeneity are critical factors of excavation disturbance in deep rock. However, at present, there are few engineering practices used in deep resource mining, and it is difficult to analyse the high in situ stress and dynamic three-dimensional (3D) excavation process in laboratory experiments. As a result, an understanding of the behaviours and mechanisms of the dynamic evolution of the stress field and plastic zone in deep tunnelling and mining surrounding rock is still lacking.Design/methodology/approachThis study introduced a 3D engineering-scale finite element model and analysed the scheme involved the elastoplastic constitutive and element deletion techniques, while considering the influence of the deep rock mass of the roadway excavation, coal seam mining-induced stress, plastic zone in the process of mining disturbance of the in situ stress state, excavation rate and layered rock mass properties at the depths of 500 m, 1,500 m and 2,500 m of several typical coal seams, and the tunnelling and excavation rates of 0.5 m/step, 1 m/step and 2 m/step. An engineering-scale numerical model of the layered rock and soil body in an actual mining area were also established.FindingsThe simulation results of the surrounding rock stress field, dynamic evolution and maximum value change of the plastic zone, large deformation and settlement of the layered rock mass are obtained. The numerical results indicate that the process of mining can be accelerated with the increase in the tunnelling and excavation rate, but the vertical concentrated stress induced by the surrounding rock intensifies with the increase in the excavation rate, which becomes a crucial factor affecting the instability of the surrounding rock. The deep rock mass is in the high in situ stress state, and the stress and plastic strain maxima of the surrounding rock induced by the tunnelling and mining processes increase sharply with the excavation depth. In ultra-deep conditions (depth of 2,500 m), the maximum vertical stress is quickly reached by the conventional tunnelling and mining process. Compared with the deep homogeneous rock mass model, the multilayered heterogeneous rock mass produces higher mining-induced stress and plastic strain in each layer during the entire process of tunnelling and mining, and each layer presents a squeeze and dislocation deformation.Originality/valueThe results of this study can provide a valuable reference for the dynamic evolution of stress and plastic deformation in roadway tunnelling and coal seam mining to investigate the mechanisms of in situ stress at typical depths, excavation rates, stress concentrations, plastic deformations and compression behaviours of multilayered heterogeneity.

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“…The thickness of the coal seam is more than 3.5 m, which is called the thick coal seam 1 , and it is the main mineable coal seam to achieve high production and high efficiency in modern Chinese mines 2 . According to incomplete statistics, about 46% of China's coal resource reserves and production come from the mining of thick coal seams 3 .…”

Section: Introductionmentioning

confidence: 99%

Supporting optimization of thick seam roadway with top coal based on orthogonal matrix analysis

Jia

Fan

et al. 2023

Sci Rep

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Aiming at the problem of large deformation and difficulty in surrounding rock control of the top coal roadway in thick seam, theoretical analysis, theoretical analysis, numerical simulation, orthogonal matrix analysis and other methods were used to study the roof deformation and support parameter optimization of the top coal roadway in thick seam. Firstly, the structural model and roof mechanical model of the top coal roadway in thick seam were established, and the deformation coefficient TK was defined based on the relationship between curvature radius and bending moment, maximum bending moment and ultimate tensile strength of beam. According to the ratio of deformation rate between TK and beam to determine the roof deformation mode of top coal roadway, the discriminant conditions of roadway roof stability under two deformation conditions are obtained. Due to the characteristics of serious coal-rock fragmentation, large roof deformation, and integration of top coal and side coal. Therefore, the combined support method of “high prestressed long and short anchor cables” is proposed by double arch bearing structure control technology. Finally, based on the orthogonal matrix analysis method of supporting parameters optimization of the top coal roadway in thick seam, the analysis amount of supporting scheme is significantly reduced, the comprehensive evaluation of multi-factor and multi-supporting effect of roadway support is realized, and the optimal supporting scheme is obtained. Compared with the surrounding rock of the roadway without support, the deformation of the roof is reduced by 27.27%, the deformation of the two sides is reduced by 45.24%, and the tensile failure volume is reduced by 54.66%. The top coal roadway in thick seam has been effectively controlled, which provides guarantee for high yield and high efficiency of the mine.

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Research on the overburden deformation and migration law in deep and extra-thick coal seam mining

Cited by 28 publications

References 9 publications

Geoelectric field response characteristics analysis of floor roadway surrounding rock fracture caused due to coal seam mining

Geoelectric field response characteristics analysis of floor roadway surrounding rock fracture caused due to coal seam mining

Numerical analysis for mining-induced stress and plastic evolution involving influencing factors: high in situ stress, excavation rate and multilayered heterogeneity

Supporting optimization of thick seam roadway with top coal based on orthogonal matrix analysis

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