An Experimental and Analytical Research on the Evolution of Mining Cracks in Deep Floor Rock Mass

Chen, Juntao; Zhao, Jun; Zhang, Shichuan; Zhang, Yi; Yang, Fan; Li, Ming

doi:10.1007/s00024-020-02550-9

Cited by 71 publications

(48 citation statements)

References 23 publications

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“…Gangue discharge and surface subsidence control are common problems in coal mining. For a long time, the technology of gangue backfilling mining has developed into an effective means to control the strata movement and surface subsidence and has been widely applied [11][12][13][14][15][16][17]. The gangue of the main component in filling body of goaf [18,19] is in a state of long-term pressure deformation, and its long-term bearing characteristics determine the stability of the overlying strata and filling effect of the goaf [20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Effects of Water Immersion on the Long-Term Bearing Characteristics of Crushed Gangue in Goaf

Ning

Yin

et al. 2021

Geofluids

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To study the long-term bearing characteristics of crushed gangue in goaf under water immersion conditions, the creep test of the crushed gangue in the water immersion state was performed by using the self-developed large-scale deformation-seepage test system of crushed rock. The effects of the rock lithology, axial stress, and grain composition on the long-term bearing deformation characteristics and fractal characteristics of crushed gangue under water immersion were analysed. The results show that under certain conditions of axial stress and grain composition of the gangue, a greater uniaxial compressive strength of water-saturated rock corresponds to a greater deformation resistance of the rock, smaller strain and crushing expansion in the corresponding creep stage, and greater fractal dimension increments of the crushed gangue after compression, and the gangue will have more serious crushing. With identical grain compositions and with the increase in the axial stress in the creep stage, the strain increases, the crushing expansion decreases, the fractal dimension increments of the crushed gangue after compression increase, and the gangue will have more serious crushing. Under identical axial stress conditions, when the Talbol power index n is 0.5, the differentials of the strain and crushing expansion for the crushed sandstone sample in the creep stage are minimal. When n is 0.3 or 0.7, these quantities are basically equal. With the increase in the Talbol power index, the fractal dimension increments of the crushed sandstone sample during compression gradually increase, and the crushed sandstone sample will have more serious crushing.

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Section: Introductionmentioning

confidence: 99%

Effects of Water Immersion on the Long-Term Bearing Characteristics of Crushed Gangue in Goaf

Ning

Yin

et al. 2021

Geofluids

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“…Moreover, the radius of pores varies among different regions, and determining the proportion of each region was of great signifi-cance [12,14]. Thus, the combination of various experiments and the calculation of the percentage of pores with different radius were important to the analysis of the characterization of shale pore structure [15][16][17]. After those steps, the multifractal characteristics, origin of subpore features (for example, surface roughness and heterogeneity) could be investigated from the perspective of relationships among multifractal dimensions, mineral compositions, and pore structures [16].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Shale Pore Structure by Multitechnique Combination and Multifractal Analysis and Its Significance

et al. 2020

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Understanding pore structure would enable us to obtain a deeper insight into the fluid mechanism in porous media. In this research, multifractal analysis by various experiments is employed to analyze the pore structure and heterogeneity characterization in the source rock in Ordos Basin, China. For this purpose, imaging apparatus, intrusion tests, and nonintrusion methods have been used. The results show that the objective shale reservoir contains complex pore network, and minor pores dominant the pore system. Both intrusion and nonintrusion methods detected pore size distributions show multifractal nature, while the former one demonstrates more heterogeneous features. The pore size distributions acquired by low temperature adsorption and nuclear magnetic resonance have relatively good consistence, indicating that similar pore network detection method may share the same mechanism, and the full-ranged pore size distributions need to be acquired by multitechniques. Chlorite has an obvious impact on the heterogeneity of pore structure in narrow pore size range, while illite and I/S mixed layer influence that in wide range. Kerogen index is the fundamental indicators of geochemical parameters. With the decrease of averaged small and middle/large pore radius, the heterogeneity of pore structures increase in narrow and wide ranges, respectively. This work employed a comprehensive methodology based on multitechniques and helps to explore how pore networks affect reservoir quality in shale reservoirs.

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“…Liu et al [16] conducted a numerical simulation of the bending deformation of the underground casing and used finite element analysis to analyze the relationship between the bending deformation of the underground casing and the effective diameter and failure ranges of the cement and rocks in the strata. ey found that the cement sheath failure at the position of the casing deformation ranged from 0.5 m to 0.8 m, and the strata failure around the cement sheath ranged from 1.0 m to 1.5 m. e rupture characteristics of the gas extraction surface hole in the mining area were investigated by Li et al [17][18][19], based on which some protection measures (i.e., local well cementation, hanger completion, and a special casing) were proposed. Additionally, three different well structures were designed and put into use in a mining area.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Physical Similarity Simulation of the Deformation and Failure of a Gas Extraction Surface Well in a Mining Area

Sun

Wen

et al. 2020

Advances in Civil Engineering

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Surface well deformation and failure in a mining area are a key issue challenging the surface well gas extraction technique. To provide information for the design of gas extraction surface wells in mining areas, the deformation and failure of surface wells with different materials under the influence of mining-induced rock movement were analyzed based on a three-dimensional physical similarity simulation and key strata theory. The research findings reveal that the fractures in the overlying strata had an elliptic-parabolic shape. The stope center was the highest point in the fracture zone. Horizontal shear deformation was most likely to occur in the thick strata (horizontal shear deformation could be larger if they were key strata) with large strength and stiffness near the intersection between the fracture surface of the overlying strata and the surface well. Due to the shear force and bending moment of the key strata, the surface well deformed into an S-shape. In addition, the surface well was vulnerable to shear deformation in the key strata. The surface well deformation did not weaken from bottom to top due to rock movement. Instead, it was subject to the influence of the rupture strength of the key strata. The surface well above the key strata was prone to tensile strain-compressive strain transition. In contrast, an abrupt change in the compressive strain occurred in the surface well below the key strata where tensile failure may occur. Moreover, a mechanical model of the surface well during the movement of the key strata was established according to the characteristics of the surface well deformation. The test results provide important information on the design optimization of surface wells and high-risk area protection in mining areas.

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An Experimental and Analytical Research on the Evolution of Mining Cracks in Deep Floor Rock Mass

Cited by 71 publications

References 23 publications

Effects of Water Immersion on the Long-Term Bearing Characteristics of Crushed Gangue in Goaf

Effects of Water Immersion on the Long-Term Bearing Characteristics of Crushed Gangue in Goaf

Characterization of Shale Pore Structure by Multitechnique Combination and Multifractal Analysis and Its Significance

Three-Dimensional Physical Similarity Simulation of the Deformation and Failure of a Gas Extraction Surface Well in a Mining Area

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