Inclination effect of coal mine strata on the stability of loess land slope under the condition of underground mining

Sun, Xue Yang; Ho, Chun Hsing; Li, Cheng; Xia, Yucheng; Zhang, Qi

doi:10.1007/s11069-020-04193-4

Cited by 5 publications

(3 citation statements)

References 7 publications

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“…In this simulation, a uniformity coefficient is used to evaluate the physical property uniformity in coal and rock materials. The actual mechanical properties of coal and rock materials are connected to uniformity, and these values are used to input the micromechanical parameter values for the numerical simulation [45][46][47]. The Weibull distribution is used to assign properties to the coal and rock materials, while the damage constitutive relationship is based on the Mohr-Coulomb criterion [48,49].…”

Section: Test Results Of Coal Seam Hydraulicmentioning

confidence: 99%

Research on Hydraulic Fracturing Technology of Long Boreholes along Strata of High Vast Thick Coal Seam

Wang,

Li,

Liu

et al. 2024

Advances in Civil Engineering

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Gas extraction is a major technique for regional gas regulation and coal and gas comining in China. Assuring effective gas extraction operations is a crucial step in ensuring the supply of energy. The effect range of extraction drilling, pressure relief degree, and standard period of gas extraction are all constrained because of the geological constraints affecting coal gas permeability and occurrence. Combined with the advantages of directional drilling and high-efficiency pumping technology and antireflection enhanced pumping technology of hydraulic fracturing, directional long-drilling hydraulic fracturing can effectively improve the efficiency of gas control and expand the scale of gas control. The present study focuses on the exploration of directional long-hole hydraulic fracturing technique in thick coal seams with high gas content using Dafosi Mine as a case study. The research findings demonstrate that hydraulic fracturing contributes to the enlargement of pore size, pore density, and pore connectivity in coal seams. In-depth research was conducted on the expansion of coal seam fractures during the hydraulic fracturing process using the RFPA3D-flow numerical simulation program. Additionally, a comprehensive analysis of stress distribution around the fractures under the flow-solid coupling condition was performed. To further improve the effectiveness of hydraulic fracturing technique, the research team optimized the fracturing tools and construction processes in the four coal seams of Dafosi Mine. The impact of segmented hydraulic fracturing in coal seam bare hole drilling was also studied. Furthermore, an investigation method specific to the coal seam bare hole segmented hydraulic fracturing effects applicable to Dafosi Mine was developed. The maximum fracture extension pressure, minimum fracture closure pressure, and fracture morphology change characteristics during drilling and fracturing were measured, and the fracturing influence radius of coal seam was determined to be 46−58 m, the gas extraction concentration after fracturing increased by 2.20–4.22 times, and the 100-m extraction flow increased by 4.93–11.03 times. It gives other mines technical assistance so they can keep advocating and utilizing the horizontal directional long-drilling stage hydraulic fracturing technique.

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Section: Test Results Of Coal Seam Hydraulicmentioning

confidence: 99%

Research on Hydraulic Fracturing Technology of Long Boreholes along Strata of High Vast Thick Coal Seam

Wang,

Li,

Liu

et al. 2024

Advances in Civil Engineering

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“…However, when mining coal seams under soil slopes, the goaf formed by mining changes the original stress equilibrium state of the slope, leading to phenomena such as slope collapse and landslides in mining areas [3,4]. These unstable slopes not only pose a serious threat to the lives of residents but also damage farmland vegetation, exacerbating soil erosion and desertification [5,6].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Soil Slope Stability under Underground Coal Seam Mining Using Improved Radial Movement Optimization with Lévy Flight

Li,

Jin,

Liu

2024

Mathematics

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Underground coal seam mining significantly reduces the stability of slopes, especially soil slopes, and an accurate evaluation of the stability of soil slopes under underground mining conditions is crucial for mining safety. In this study, the impact of coal seam mining is considered as the additional horizontal and vertical stresses acting on the slope, and an equation for calculating the safety factor of soil slopes under underground mining conditions is derived based on the rigorous Janbu method. Then, the Improved Radial Movement Optimization (IRMO) algorithm is introduced and combined with Lévy flight optimization to conduct global optimization searches, obtaining the critical sliding surface and corresponding safety factor of the soil slope under underground coal seam mining. Through comparisons with the numerical simulation results in three different case studies, the feasibility of applying the IRMO algorithm with Lévy flight to analyze the stability of soil slopes under underground mining is demonstrated. This ensures the accuracy and stability of the calculation results while maintaining a high convergence efficiency. Furthermore, the effects of the mining thickness and mining direction on slope stability are analyzed, and the results indicate that a smaller mining thickness and mining along the slope are advantageous for slope stability. The method proposed in this study provides valuable insights for preventing the slope instability hazards caused by underground coal seam mining.

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“…Liang et al [21] proposed the two-dimensional hydraulic-mechanical calculation model and the key-strata stability analysis model to analyze the theoretical range of failure and the stability of inclined floor strata after mining. Sun et al [22] investigated the inclination effect of mine strata on the stability of loess land slope under the condition of underground mining. Wang et al [23] proposed DFH control strategies of the tunnel driven in deep inclined strata.…”

Section: Introductionmentioning

confidence: 99%

An Innovative Balanced-Yielding Support Method for Tunnel in Deep Inclined Strata

et al. 2022

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Aiming at the problem that the uneven deformation of the tunnel surrounding rock in the deep inclined rock strata caused local instability, an innovative balanced-yielding support technology was proposed with the engineering background of the Shangping tunnel in Huafeng Mine. Based on the mechanism analysis of this technology, the specific implementing steps were proposed. It mainly included in situ stress analysis, the stress distribution of the tunnel surrounding rock with different sections, the design of the parameter of bolt-cable and yielding structure, and supporting effect evaluation. The results showed that (1) the stress concentration appeared at the top corners of the lower side and the bottom corner of the upper side of the rectangular and semicircular arched tunnel. (2) Compared with rectangle and vertical-wall semicircular arch tunnels, the trapezoidal tunnel could relieve the shearing effect of the inclined rock strata. (3) The length, prestress, spacing-row distance of the bolt, and the parameter of the yielding structure were all optimally designed to form the balanced-yielding support system. (4) In engineering application, the maximum deformations of the roof, right side and left side, were less than 80 mm. Compared with the original support system, the shallow separation of the trapezoidal tunnel supported by the balanced-yielding support system had been reduced by 147%.

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Inclination effect of coal mine strata on the stability of loess land slope under the condition of underground mining

Cited by 5 publications

References 7 publications

Research on Hydraulic Fracturing Technology of Long Boreholes along Strata of High Vast Thick Coal Seam

Research on Hydraulic Fracturing Technology of Long Boreholes along Strata of High Vast Thick Coal Seam

Analysis of Soil Slope Stability under Underground Coal Seam Mining Using Improved Radial Movement Optimization with Lévy Flight

An Innovative Balanced-Yielding Support Method for Tunnel in Deep Inclined Strata

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