Degradation of physical and mechanical properties of sandstone subjected to freeze-thaw cycles and chemical erosion

Jian, Zhang; Deng, Hongwei; Taheri, Abbas; Ke, Bo; Liu, Chuanju; Yang, Xiangru

doi:10.1016/j.coldregions.2018.07.007

Cited by 93 publications

(23 citation statements)

References 26 publications

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“…However, when the number of F-T cycles increased from 10 to 30, the proportion showed fluctuations. This is mainly because the chemical reaction product of H 2 SO 4 solution and rock minerals is poorly water-soluble and may fill the initial pores and expanded pores caused by F-T cycles [30], [56]. On the one hand, it was observed that for the other three groups, the proportion of mini-pores and mesopores both decreased, while the proportion of macropores increased with an increase in F-T cycles.…”

Section: Pore Structure Developmentmentioning

confidence: 98%

“…As for the fractal dimension of macropores D 3 , it was found that D 3 of the NaOH and NaCl groups decreased while increased for groups of H 2 SO 4 and pure water, indicating that the pore structure of the macropores became more complex in H 2 SO 4 solution and pure water, while macropores became more uniform in NaOH and NaCl solutions. This is may be attributed that when immersed in H 2 SO 4 solution and pure water, the chemical products are poorly water-soluble and may fill the initial pores and expanded pores caused by F-T cycles [30], [56].…”

Section: A Fractal Dimensions Of Different Poresmentioning

confidence: 99%

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Fractal Analysis of Pore Structure Development of Sandstone: A Nuclear Magnetic Resonance Investigation

Zhang

Deng

et al. 2019

IEEE Access

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The pore structure of rock has a great influence on its physical and mechanical properties. Factors such as chemical corrosion and temperature changes affect the pore structure evolution. In this paper, the pore structure of sandstone was investigated under rapid freeze-thaw (F-T) cycles and chemical corrosion. A nuclear magnetic resonance (NMR) testing system is used to study the pore structure of tight sandstone samples immersed in different chemical solutions after 10, 20, and 30 F-T cycles. Permeability is determined by using empirical method. Results found that permeability is strongly affected by the erosion of NaOH and NaCl solutions. The pores in the rock were divided into three categories based on the pore size, i.e., minipores, mesopores, and macropores. The results showed that the amount of mini-pores and mesopores both decreased with an increase in the number of F-T cycles while the amount of macropores increased for groups of NaOH, NaCl, and pure water. No conclusive trend can be found in the H 2 SO 4 group. Fractal analysis of the pore structure revealed that no conclusive trend was observed for fractal dimension of mini-pores D 1 . Fractal dimension of mesopores D 2 ranged from 2.79 to 2.93, indicating a medium complexity pore structure of the mesopores. Fractal dimension of macropores D 3 was over 2.9, implying that the pore structure of the macropores is the most complex. The fractal dimension of the T 2 spectrum D NMR ranged from 2.55 to 2.77. Correlations between the fractal dimensions and porosity are also presented. Results showed that D 2 and D 3 can be good indicators for the pore size volume of sandstone samples immersed in H 2 SO 4 , NaOH and NaCl solutions, while D NMR is a good indicator for the pore size volume of sandstone samples immersed in NaOH solution and pure water.INDEX TERMS Pore structure, freeze-thaw, chemical corrosion, nuclear magnetic resonance, fractal analysis.

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Section: Pore Structure Developmentmentioning

confidence: 98%

Section: A Fractal Dimensions Of Different Poresmentioning

confidence: 99%

Fractal Analysis of Pore Structure Development of Sandstone: A Nuclear Magnetic Resonance Investigation

Zhang

Deng

et al. 2019

IEEE Access

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“…Then, saturated samples were immersed into an acid solution and placed into the F-T test machine for F-T treatment. During the F-T treatment, the temperature range was set as −20 • C to 20 • C [10,16,18,23]-both the freezing phase and the thawing phase last 4 h. Samples were taken out of the machine for other detections and measurements after every 10 F-T cycles.…”

Section: Freeze-thaw Testmentioning

confidence: 99%

Microscopic Characteristic Analysis on Sandstone under Coupling Effect of Freeze–Thaw and Acidic Treatment: From Nuclear Magnetic Resonance Perspective

Deng

Tian

et al. 2020

Applied Sciences

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Microscopic characteristics greatly affect mechanical and physical properties as they exert vital impact on the stability and durability of materials. In this paper, widely distributed sandstone was chosen as the research object. Sandstone was treated with a coupled effect of Freeze–Thaw (F–T) weathering and acid solution, where freeze–thaw cycles were set as 0, 10, 20, 30 and 40 cycles, and the pH of the acid solution were set as 2.8, 4.2, 5.6 and 7.0, respectively. Then, nuclear magnetic resonance was applied to measure the microscopic characteristics of sandstone, then porosity, pore size distribution and permeability before the fractal dimensions were obtained and calculated. Results show that porosity increases when F–T cycles increase, and its increase grows with the pH of acid solution decrease during the first 10 F–T cycles. Macro porosity, meso porosity and micro porosity account for the largest, second largest and smallest ratio of porosity growth. Meso porosity, micro porosity and macro porosity account for the largest, second largest and smallest ratio of total porosity. Permeability increases obviously with F–T cycle increase, while acid erosion exerts little influence on permeability increment overall. Fractal dimensions of meso pores and macro pores increase with F–T cycle increase overall, and they increase with pH decrease overall. Porosity has strong exponentially correlation with permeability. Fractal dimensions of meso pores and macro pores have good linearly correlation with permeability, while correlation between porosity and fractal dimensions are not that obvious.

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“…The freezing method is an excavation technique using artificial refrigeration to temporarily consolidate the wall rock in an aquifer. The strengths (e.g., compressive and tensile strength) of rocks in frozen and unfrozen states are significantly different [5,6]. Hence, more attention should be paid to the mechanical strengths and failure modes of both frozen and unfrozen rocks [7,8].…”

Section: Introductionmentioning

confidence: 99%

“…Previous investigations indicated that rock compressive and tensile strengths in subzero temperatures were increased as the temperatures were reduced, and the temperature had a more significant effect on the tensile strength than compressive strength [22,23,24,25]. Recently, Zhang et al systematically investigated the physical and mechanical properties of sandstone subjected to freeze–thaw cycles, chemical erosion, and cyclic loading, and the results implied that the porosity was a key factor attributed to sandstone strength degradation [5,6]. Liu et al proposed that the combined coal–rock body experienced strain recovery, and this played a loading effect on the failure of the coal [26].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Mechanical Characteristics and Fracture Patterns of Unfrozen/Freezing Saturated Coal and Sandstone

Wang

Zhang

et al. 2019

Materials

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The thermomechanical behavior of coal and sandstone during excavation using the freezing method is a new challenge for coal mining and geotechnical engineering. In this paper, the influence of temperature on the mechanical characteristics and fracture patterns of two types of saturated rocks (coal and sandstone) were investigated. A series of laboratory tests, including the Brazilian tensile strength (BTS), uniaxial compressive strength (UCS), and triaxial compressive strength (TCS), were conducted at temperatures of 20, −4, −10, and −15 °C. The results indicated a significant increase in their strength when the temperature was reduced from 20 to −15 °C, especially near the phase-transition point. Then, a theoretical model was proposed to predict rock strength change with temperature, based on the phase-transition theory. To evaluate this model, the predicted results were compared with experimental data, where a good correlation was identified. In addition, four failure patterns were observed in indirect tensile tests (i.e., layer activation, central fracture, noncentral fracture, and central and layer activation), and three types of failure modes in compression tests (i.e., axial splitting, shearing along a single plane, multiple fracturing). The evolution of the rock damage was divided into four stages: Crack closure, fracture initiation, critical energy release, and rupture. These results could be applied to evaluate and predict the mechanical behavior of saturated coal and sandstone during excavation using the freezing method.

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Degradation of physical and mechanical properties of sandstone subjected to freeze-thaw cycles and chemical erosion

Cited by 93 publications

References 26 publications

Fractal Analysis of Pore Structure Development of Sandstone: A Nuclear Magnetic Resonance Investigation

Fractal Analysis of Pore Structure Development of Sandstone: A Nuclear Magnetic Resonance Investigation

Microscopic Characteristic Analysis on Sandstone under Coupling Effect of Freeze–Thaw and Acidic Treatment: From Nuclear Magnetic Resonance Perspective

Experimental Study on Mechanical Characteristics and Fracture Patterns of Unfrozen/Freezing Saturated Coal and Sandstone

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