Development, Performance, and Microscopic Analysis of New Anchorage Agent with Heat Resistance, High Strength, and Full Length

Liu, Xiaohu; Yao, Zhishu; Xue, Weipei; Li, Xiang

doi:10.1155/2019/4239486

Cited by 3 publications

(4 citation statements)

References 8 publications

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“…As shown in Figure 7, the general graph of stress-strain curves was obtained on the basis of multiple sets of compressive tests. The overall law of the curve change was basically the same, and similar results can be found in existing studies [27,28]. The development of curves show that the compression stress first rose rapidly to the peak value, then turning into a falling section and decaying thus to the residual strength.…”

Section: Fracture Failure Processsupporting

confidence: 86%

Section: Peak Stress and Strainmentioning

confidence: 99%

“…As shown in Figure 9, Sr was always less than 1.0 under all VTC conditions, which means that the mechanical strength of grouting material in high-geothermal environments decreased to different degrees compared to normal conditions. That is why some engineering problems like failures in advanced pipe grouting or anchorage systems usually occur a long time after construction in high-geothermal tunnels [28][29][30]. According to the relative peak strength, values of Sr under the conditions of different curing factors were obtained, and the higher the temperature, the lower the relative humidity, the more the compressive strength of grouting material declined.…”

mentioning

confidence: 99%

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Mechanical Characteristics of Cement-Based Grouting Material in High-Geothermal Tunnel

Wang

Jiang

et al. 2020

Materials

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The cement-based grouting materials used for practical purposes in high-geothermal tunnels are inevitably affected by humidity and high temperature, leading to the deterioration of mechanical properties. Based on the characteristics of changing high temperatures and two typical conditions of hot-humid and hot-dry environments in high-geothermal tunnels, many mechanical strength tests were carried out on the grouting material cured under different environmental conditions. The study results indicated that high temperature and low relative humidity were unfavorable to the development of mechanical characteristics of grouting material, but the coupling effect of two factors could improve the strength at early ages and reduce the degradation of long-term strength. As the curing temperature exceeded 56.3 °C, the humidity effect on strength played a more important role in recovering the strength of grouting material damaged by high temperature. Temperature had more significant impact on the relative peak stress while the relative humidity had greater influence on the relative peak strain. A calculation compressive constitutive model was prospered, which considering both temperature and relative humidity. The study results may provide much valuable experimental data and theoretical supporting for the design of compression constitutive of cement-based grouting material in high-geothermal tunnel.

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Section: Fracture Failure Processsupporting

confidence: 86%

Section: Peak Stress and Strainmentioning

confidence: 99%

mentioning

confidence: 99%

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Mechanical Characteristics of Cement-Based Grouting Material in High-Geothermal Tunnel

Wang

Jiang

et al. 2020

Materials

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“…However, when the local temperature of the anchorage agent is too high, the compressive strength of the PET resin anchorage agent decreases too much, which could easily cause support failure. Given this situation, we developed a new type of anchorage agent, anchorage agent l, based on the existing PET anchorage agent mixed with FX-470 resin to modify the mixing of PET and KH-570, and obtained a resin anchorage agent with high strength and excellent heat resistance to solve the problem of anchorage loss in high-temperature ground [31]. stretching vibration of the unsaturated double bond C=C in polyester is at 1690 cm −1 , and the peak at 1400 cm −1 can be ascribed to the symmetric stretching vibration of ethereal groups C-O-C. e peaks at 876 cm −1 and 730 cm −1 are derived from C-H group in benzene ring of p-phenyl-type [29].…”

Section: Ftir Scanning Analysismentioning

confidence: 99%

Effect of Temperature and Accelerator on Gel Time and Compressive Strength of Resin Anchoring Agent

Liu

Yao

Xue

et al. 2019

Advances in Polymer Technology

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In this study, we examined the effects of different temperatures and accelerators on the gelation (gel) time and compressive strength of a Polyethylene Terephthalate (PET)-type unsaturated polyester resin anchorage agent. First, the formation temperature of 20–70°C was simulated using self-made test equipment. N,N-Dimethylaniline (DMA), N,N-dimethylp-toluidine (DMT), and hydroquinone were selected as accelerators to determine gel time and heat release peak. The gel time of an anchorage agent is strongly influenced by accelerant and temperature. When DMT, DMA, and hydroquinone were added at the same temperature, the gelation time increased; with increasing ambient temperature, the gelation time of the anchorage agent decreased. The peak exothermic value of the curing reaction was less affected by the accelerator, and the peak exothermic value of the anchoring agent increased with the increase in ambient temperature. Then, the compressive strength of the anchorage agent, maintained at 20, 50, and 80°C for 1.5, 6, 12, and 24 h, was measured. We found that the compressive strength of resin anchorage agent decreased significantly with the increase in temperature, and the addition of DMT can improve the compressive strength of resin anchorage agent slightly at the same temperature conditions. Finally, through Fourier transform infrared scanning analysis, we determined the intrinsic causes of the influence of temperature and accelerator on the gelation time and compressive strength of the anchorage agent. Through SPSS fitting analysis, an empirical formula for predicting gelation time based on ambient temperature is proposed. Our findings provide a basis for reasonable mixing time and support design optimization of anchorage support in deep stratum in high-temperature geothermal environments.

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Experimental Study of the Failure Mechanism of the Anchorage Interface under Different Surrounding Rock Strengths and Ambient Temperatures

Liu

Yao

Xue

et al. 2021

Advances in Civil Engineering

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In order to study the anchoring instability mechanism of surrounding rock in deep roadway, the failure mechanism of the bolt-anchoring agent interface was studied by simulating different strength rock mass and ground temperature environment, using C20, C40, and C60 strength concrete and steel pipe to simulate different surrounding rock strength environments. Indoor pull-out tests were carried out to study the pull-out load displacement relationship, ultimate pull-out force, residual anchoring force, the distribution law of axial stress and tangential stress along the bar, and the energy consumption value of drawing failure at 20, 50, and 70°C. The test results show that, with the decrease of surrounding rock strength or the increase of ambient temperature, the pull-out force, residual anchoring force, and energy consumption value of anchorage interface gradually decrease; under different axial forces, the axial force distribution of the rod body decreases exponentially from the anchoring end to the opposite end; and the shear stress transfers to the deep part of the anchor body with the increase of the load. According to the failure phenomenon of the specimen, the failure modes of the bolt bolt-anchorage agent interface can be divided into shear slip mode and shear expansion slip mode. The shear expansion slip formula of anchorage interface is derived. Using high-strength and temperature-resistant resin anchoring agent for comparative test, the rationality of the mechanism analysis is proved, which provides more clear guidance for the construction of anchor support.

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Development, Performance, and Microscopic Analysis of New Anchorage Agent with Heat Resistance, High Strength, and Full Length

Cited by 3 publications

References 8 publications

Mechanical Characteristics of Cement-Based Grouting Material in High-Geothermal Tunnel

Mechanical Characteristics of Cement-Based Grouting Material in High-Geothermal Tunnel

Effect of Temperature and Accelerator on Gel Time and Compressive Strength of Resin Anchoring Agent

Experimental Study of the Failure Mechanism of the Anchorage Interface under Different Surrounding Rock Strengths and Ambient Temperatures

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