A novel sealing material and a bag-grouting sealing method for underground CBM drainage in China

Fu, Jianhua; Li, Xuelong; Wang, Zhiming

doi:10.1016/j.conbuildmat.2021.124016

Cited by 15 publications

(8 citation statements)

References 23 publications

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“…The virgin state of stress of the surrounding coal rock is destroyed by a drilling dynamic disturbance during the construction of the roadway and borehole, while the ambient stress is redistributed after drilling. According to the distribution characteristics of the stress field and elastic-plastic theory, “three belts and four zones” are formed around the borehole. − That is, from the coal (rock) wall of the roadway to its deep part, the axial direction of the borehole, the fracture zone, stress concentration belt, and original rock stress belt are successively presented (Figure a), corresponding to the fracture zone, plastic zone, elastic zone, and original rock stress zone along the radial direction of the borehole, respectively (Figure b). The surrounding rock in the fracture zone is highly fractured, and the internal cracks rapidly develop and connect, which forms the stress reduction zone.…”

Section: The Basic Principles Of Hole Sealing Technology Of Solid–liq...mentioning

confidence: 99%

The Hole Sealing Technology of Solid–Liquid Materials with Three Pluggings and Two Injections for Gas Extraction Hole in the Coal Mine

Song

et al. 2022

ACS Omega

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The sealing quality of the gas extraction holes determines the extracted gas concentration. Based on this, the paper reveals the basic principle of hole sealing by analyzing the gas leakage mechanism of the borehole. The hole sealing technology of solid–liquid materials with three pluggings and two injections for the gas extraction hole is proposed, and the hole sealing device and material are developed. Through testing the granularity distribution of the solid material, as well as the surface tension and contact angle of the slurry, the hole sealing material that can meet the requirements of accessible, sticky, and anti-deformation is selected. The sealing material enters microcracks and bonds coal rock more easily. First, the solid material is injected for hole sealing. Second, the liquid material can be injected repeatedly to maintain a high concentration for holes with poor sealing and gas concentration attenuation in the late stage of gas extraction. Field tests show that the gas concentration of solid material is 1.3 times that of the conventional material after 30 days of sealing. The liquid material injected after the concentration decline enables the gas extraction concentration to be recovered at 85%.

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Section: The Basic Principles Of Hole Sealing Technology Of Solid–liq...mentioning

confidence: 99%

The Hole Sealing Technology of Solid–Liquid Materials with Three Pluggings and Two Injections for Gas Extraction Hole in the Coal Mine

Song

et al. 2022

ACS Omega

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“…Coalbed methane (CBM) is a high-heat, clean energy source, with a heat generation of about (3.35–3.77) × 10 5 J/m 3 of CBM, − equivalent to the heat of 1 kg of standard coal, and the pollution it produces is only 1/40 of that of oil and 1/800 of that of coal. − It can be seen that methane has a very large potential as a common fuel and chemical raw material. − For the mine types of CBM outburst mines and high CBM mines, the simultaneous extraction of coal and CBM is the best measure for the utilization of coal mine CBM resources and the control of CBM disasters. − The seepage law of CBM in coalbeds is one of the basic problems in the research field of coal mine CBM disaster prevention and control, which has important guiding significance for the basic theoretical research on CBM outburst, CBM extraction, and coal and CBM outburst prevention and control. − …”

Section: Introductionmentioning

confidence: 99%

Fluid–Solid Coupling Characteristics of Methane-Containing Coal during Borehole Extraction of Coalbed: Numerical Modeling and Experimental Research

Yan,

Wen,

Jin

et al. 2023

ACS Omega

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The control and utilization of coalbed methane (CBM) are crucial for ensuring the safety of coal mining operations and mitigating greenhouse gas emissions. Predrainage of CBM from boreholes plays a pivotal role in preventing CBM accidents, harnessing CBM energy resources, and reducing greenhouse gas emissions. To better understand the evolution of key parameters during the predrainage process of CBM boreholes, this study, based on fundamental assumptions of coupling models, integrates the theories of elasticity, seepage mechanics, and fluid mechanics. It establishes a comprehensive mathematical model that reveals the interrelationships among the stress field, deformation field, and seepage field within methane-containing coal systems. By comparing numerical solutions with analytical solutions and conducting physical similarity simulation experiments, the study demonstrates the correctness of the methane-containing coal fluid–solid coupling model. The model developed in this study represents an improvement over traditional methane-containing coal seepage theories and fluid–solid coupling model theories and can be widely applied in the prevention of coal and CBM outbursts as well as CBM extraction.

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“…The injected slurry is guaranteed to not spill into the surrounding soil, which can cause environmental pollution. Pouch grouting is mainly used in sealing pipes [22,23], filling cracks [24,25], and reinforcing foundations [26,27]. It is also used in new structures, such as pouch grouting soil nails, pouch grouting bolts, and pouch grouting piles, that are widely used in the field of practical engineering.…”

Section: Introductionmentioning

confidence: 99%

Modeling Test and Numerical Simulation of Vertical Bearing Performance for Rigid-Flexible Composite Pouch Piles with Expanded Bottom (RFCPPEB)

et al. 2022

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Rigid-flexible composite pouch piles with expanded bottom (RFCPPEB) are generally considered as new symmetrical piles in practical engineering, but their bearing characteristics and design method are still not completely understood. The objective of this study is to investigate the vertical bearing performance and the optimal design scheme of RFCPPEB. Hence, laboratory modeling tests for this symmetric structure and an ABAQUS three-dimensional (3D) numerical simulation analysis were used to study the vertical bearing characteristics on bottom-expanded piles and rigid-flexible composite piles with expanded bottom. The vertical bearing capacity, shaft resistance, pile tip resistance distribution rule, and load sharing ratio of RFCPPEB were analyzed and verified using different bottom expansion dimensions and cemented soil thicknesses. The results revealed that the optimal bottom expansion ratio of rigid bottom-expanded piles was 1.8 when the ratio of pile body to bottom-expanded pile head was 9:1. When the bottom expansion ratio (D/d) was increased, the bearing capacity of bottom-expanded piles was significantly increased at D/d = 1.4 and D/d = 1.8 compared to that of D/d = 1.0, reaching 1.67 and 2.29 times, respectively, while for D/d = 1.6 and D/d = 2.0, the ultimate bearing capacity remained unchanged. Besides, shaft resistance played an important role in the bearing process of the rigid bottom-expanded piles and RFCPPEB. When the shaft resistance was increased, the ultimate bearing capacity of the pile foundation was significantly improved. The shaft resistance of RFCPPEB was increased with increasing cemented soil thickness. The increases in the shaft resistance and thickness of the cemented soil showed a nonlinear growth, and the maximum shaft resistance was approximately 75 cm from the pile top. When the diameter of the expanded head was 1.8 times the diameter of the pipe pile and slightly larger than the thickness of the cemented soil (0.5 times the diameter of the pipe pile), the optimal amount of concrete 425.5 kN/m3 required for per unit volume around piles was obtained, with the RFCPPEB ultimate bearing capacity of 7.5 kN. For RFCPPEB, the soil pressure at the pile tip was directly proportional to the pile top load under small load and was decreased in the form of a half quadric curve under large load. It reached the most reasonable position where the slope of the quadric curve was the largest when the thickness of the cemented soil was larger than 0.5 times the diameter of the pipe pile.

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A novel sealing material and a bag-grouting sealing method for underground CBM drainage in China

Cited by 15 publications

References 23 publications

The Hole Sealing Technology of Solid–Liquid Materials with Three Pluggings and Two Injections for Gas Extraction Hole in the Coal Mine

The Hole Sealing Technology of Solid–Liquid Materials with Three Pluggings and Two Injections for Gas Extraction Hole in the Coal Mine

Fluid–Solid Coupling Characteristics of Methane-Containing Coal during Borehole Extraction of Coalbed: Numerical Modeling and Experimental Research

Modeling Test and Numerical Simulation of Vertical Bearing Performance for Rigid-Flexible Composite Pouch Piles with Expanded Bottom (RFCPPEB)

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