Damage and Failure Evolution Mechanism for Coal Pillar Dams Affected by Water Immersion in Underground Reservoirs

Wang, Fangtian; Ningning, Liang; Li, Gang

doi:10.1155/2019/2985691

Cited by 27 publications

(14 citation statements)

References 3 publications

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“…Good stability of coal pillar dams is essential for longterm use of such groundwater reservoirs (Wang et al 2019c). Coal is a discontinuous and heterogeneous multiphase complex engineering rock mass that often contains associated minerals and irregular pores and fractures.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Coal Sample Damage in Acidic Water Environments

et al. 2021

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We investigated the effects of acidic and circumneutral water on coal samples by uniaxial compression, acoustic emission, and a series of physical tests. In acidic water, the coal samples were damaged, and their ultrasonic velocities decreased, as minerals such as kaolinite and calcite underwent dissolution. When the pH was < 7, the uniaxial compressive strength and elastic modulus decreased, while the duration of the residual strength stage tended to increase. The reactions were stronger at higher H+ concentrations and the number of large pores increased; there was a significant increase in the accumulated acoustic emission counts and maximum average energy near the unstable crack growth stage. The post-peak stage of the coal samples was characterized in the different acidic waters and the failure modes were identified by spectrum analysis. Acidic water damaged the weak areas of coal samples by complex physical and chemical reactions, which made direct tensile failure more likely when the coal samples were loaded.

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Section: Introductionmentioning

confidence: 99%

Experimental Study of Coal Sample Damage in Acidic Water Environments

et al. 2021

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“…Rock is the most common geological material in projects such as oil and gas development, coal mining, and hydroelectric power generation. In engineering practice, rocks are commonly affected by dry and wet cycles, for example, the surrounding rock of reservoir bank slope engineering by the influence of daily and seasonal changes of water level (see Figure 1) [1][2][3][4]; the thin granite veneer cladding panels installed on the exterior of buildings subjected to environmental weathering [5]; tunnel excavation under the influence of groundwater level fluctuation [6]; the slope stability of open-pit coal mine affected by rainfall (see Figure 2) [7]; the tailings pond by the impact of abandoned tailings discharge and pumping [8]; the swelling rock of the base and slope of the water conveyance channel (see Figure 3) [9][10][11]; the coastal rock masses affected by tides [12][13][14][15]; the stone monuments, sculptures, and historical sites affected by acid rain erosion [16,17]; the subgrade and surrounding rock of railway tunnel [18]; the retaining dam of an under-ground reservoir [19]. After the dry-wet cycle, the physical and mechanical properties of the rock will change to varying degrees, and the changes are very important to the design, construction, and operation of rock projects.…”

Section: Introductionmentioning

confidence: 99%

Deterioration of Physical and Mechanical Properties of Rocks by Cyclic Drying and Wetting

et al. 2021

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Both surface and underground rocks in nature often undergo repeated drying and wetting. The dry-wet cycle is a weathering effect that includes physical and chemical processes, which has varying degrees of degradation effects on the physical and mechanical properties of rocks. This paper analyzes and discusses this kind of rock degradation based on the existing literature data. First, the deterioration degree of various physical and mechanical properties (including density, P-wave velocity, porosity, static and dynamic compressive/tensile strength, and fracture toughness) is summarized as the number of dry-wet cycles increases. Secondly, the possible degradation mechanism of the dry-wet cycle is explained in terms of clay mineral swelling, solute migration, and microcrack evolution. Then, the damage constitutive model of the rock after cyclic dry-wet treatment is introduced. Finally, the issues that need to be studied in the future are put forward.

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“…In mining engineering, due to long-term precipitation and groundwater supplement, the water stored in the underground reservoir of coal mine may cause the change of acid-base property of water, which will weaken the stability of coal pillar dam structure. Under the action of earthquake or blasting and other dynamic load disturbances, the instability of coal pillar dam structure may be caused [6]. At present, the physical and mechanical properties of coal have been widely studied, such as compressive strength [7,8], tensile strength [9][10][11], fracture characteristics [12,13], elastic modulus [14], shear strength [15], and triaxial strength [16].…”

Section: Introductionmentioning

confidence: 99%

Effect of Acid and Alkaline Environment on Dynamic Strength and Porosity Characteristics of Bursting Liability Coal

Fan²,

Liu

et al. 2021

Shock and Vibration

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In order to investigate the influence of acid and alkaline environment on dynamic strength and porosity characteristics of bursting liability coal, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were used to compare the microstructures of coal with different bursting liabilities. A split Hopkinson bar (SHPB) was used to test the dynamic compressive strength and tensile strength of coal samples with different bursting liabilities. The results show that the surface micromorphology and structure characteristics of coal samples with different bursting liabilities are representatives, which can be used as an auxiliary basis to determine the bursting liability of coal seam. The microstructure of coal with strong bursting liability is characterized by mylonitic, fragmentary, and brecciated structure, and the microstructure is diverse and complex. However, the microstructure of no bursting liability coal is single and uniform. Coal with strong bursting liability shows tensile, compressive, and shear cracks produced by tectonic action, and the distribution of cracks is complicated. The development of fissures is greatly affected by the degree of coal metamorphism, organic components, minerals, and other factors. Under acidic and alkaline environments, the decrease amplitude of tensile strength of coal is obviously larger than that in neutral solution, which indicates that under the action of acid-based solution soaking, the easily soluble minerals in coal react with hydrogen ions and hydroxyl ions in solution obviously. Porosity increment in acidic environment is much larger than that in alkaline and neutral environments. The strong bursting liability coal is more sensitive to acidic environment, while the no bursting liability coal is more sensitive to alkaline environment.

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Damage and Failure Evolution Mechanism for Coal Pillar Dams Affected by Water Immersion in Underground Reservoirs

Cited by 27 publications

References 3 publications

Experimental Study of Coal Sample Damage in Acidic Water Environments

Experimental Study of Coal Sample Damage in Acidic Water Environments

Deterioration of Physical and Mechanical Properties of Rocks by Cyclic Drying and Wetting

Effect of Acid and Alkaline Environment on Dynamic Strength and Porosity Characteristics of Bursting Liability Coal

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