Mechanical Properties of GFRP Bolts and Its Application in Tunnel Face Reinforcement

Li, Huayun; Fu, Junfu; Chen, Bingguang; Zhang, Xin; Zhang, Zhiqiang; Lang, Lin

doi:10.3390/ma16062193

Cited by 6 publications

(7 citation statements)

References 24 publications

(24 reference statements)

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“…The whole tunnel model and its excavation and measuring point layout diagram are shown in Figure 4. The surrounding rock was analyzed by using the Mohr-Coulomb constitutive model [3] with eight different water contents in the surrounding rocks. The detailed mechanical parameters are shown in Figure 3.…”

Section: Analysis Of Deformation Mechanism Of Primary Support Structu...mentioning

confidence: 99%

“…When the distance between the monitoring point and the palm surface is constant, as the water content increases, the settlement of the vault also increases synchronously, and the settlement rate shows a trend of first increasing and then decreasing. During the process of increasing the distance between the monitoring point and the The surrounding rock was analyzed by using the Mohr-Coulomb constitutive model [3] with eight different water contents in the surrounding rocks. The detailed mechanical parameters are shown in Figure 3.…”

Section: Settlementmentioning

confidence: 99%

“…With the rapid development of tunnel engineering in China, it is inevitable to encounter complex and unfavorable geological strata during the construction process [1][2][3][4][5]. Among them, the loess strata, due to their obvious structure, high permeability, collapsibility, and vertical joint development [6][7][8][9][10], will face construction risks such as water leakage, large deformation, falling blocks, and collapse when constructing tunnels in this stratum [11][12][13][14]; especially, the collapsibility of loess often causes the sudden instability of the surrounding rock in a short period, leading to disasters [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Stability Assessment of Tunnels Excavated in Loess with the Presence of Groundwater—A Case Study

Deng,

Zhang,

et al. 2024

Water

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The high water content of the surrounding rock in loess tunnels will lead to the deterioration of rock strength, causing deformation and damage to the initial support structure and thereby affecting safety during construction and operation. This article first analyzes the strength characteristics of loess under different water contents through indoor physical and mechanical tests. Secondly, based on numerical simulation results, the ecological environment, and design requirements, the water content threshold is determined. Finally, a reinforcement scheme combining surface precipitation measures and curtain grouting measures is proposed, and the reinforcement effect is analyzed based on on-site monitoring data. The results show that as the water content of loess increases, the cohesion, internal friction angle, and elastic modulus of the surrounding rock all decrease, leading to an increase in the sensitivity of the surrounding rock to excavation disturbances and a deterioration in strength. During the construction process, it shows an increase in the vault settlement and sidewalls’ convergence. During the process of increasing the distance between the monitoring section and the palm face, the settlement and convergence of the tunnel show a rapid growth stage, slow growth stage, and stable stage. The water content threshold is determined to be 22%. The reinforcement scheme of combining surface precipitation measures with curtain grouting measures not only meets the requirements of the ecological environment but also makes the settlement and convergence values lower than the yellow warning deformation values required by the design.

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Section: Analysis Of Deformation Mechanism Of Primary Support Structu...mentioning

confidence: 99%

Section: Settlementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Stability Assessment of Tunnels Excavated in Loess with the Presence of Groundwater—A Case Study

Deng,

Zhang,

et al. 2024

Water

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“…Overall, the effectiveness of connections significantly influences the structural integrity and performance of CFS-built-up concrete-filled composite columns. The type of connection between steel beam elements and the degree of shear connection significantly impact the behaviour of lightweight, CFS-concrete composite floor beams [68]. Chen et al [2] conducted a test campaign concerning the behaviour of concrete-filled CFS built-up section stub columns, where a pair of identical open sections were built up to form a closed section using discrete self-tapping screws.…”

Section: Connectionsmentioning

confidence: 99%

A Critical Review of Cold-Formed Steel Built-Up Composite Columns with Geopolymer Concrete Infill

Sara Simon,

Kafle,

Al-Ameri

2024

J. Compos. Sci.

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Concrete-filled built-up cold-formed steel (CFS) columns offer enhanced load-carrying capacity, improved strength-to-weight ratios, and delayed buckling through providing internal resistance and stiffness due to the concrete infill. Integrating sustainable alternatives like self-compacting geopolymer concrete (SCGC) with low carbon emissions is increasingly favoured for addressing environmental concerns in construction. This review aims to explore the current knowledge regarding CFS built-up composite columns and the performance of SCGC within them. While research on geopolymer concrete-filled steel tubes (GPCFSTs) under various loads has demonstrated high strength and ductility, investigations into built-up sections remain limited. The literature suggests that geopolymer concrete’s superior compressive strength, fire resistance, and minimal shrinkage render it highly compatible with steel tubular columns, providing robust load-bearing capacity and gradual post-ultimate strength, attributed to the confinement effect of the outer steel tubes, thereby preventing brittle failure. Additionally, in built-up sections, connector penetration depth and spacing, particularly at the ends, enhances structural performance through composite action in CFS structures. Consequently, understanding the importance of using a sustainable and superior infill like SCGC, the cross-sectional efficiency of CFS sections, and optimal shear connections in built-up CFS columns is crucial. Moreover, there is a potential for developing environmentally sustainable built-up CFS composite columns using SCGC cured at ambient temperatures as infill.

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“…With the rapid economic development of China, more high-speed railways are under construction. As an integral part of high-speed railways, the construction scale of tunnels also increases year after year [1][2][3]. With the increase in the operation time of high-speed railway tunnels, many factors, such as lining structure damage [4], dry-wet cycle [5], special surrounding rock [6], frost heaving cycle [7], groundwater [8] and other factors may lead to safety risks, of which damage to the lining structure is one of the most important [9].…”

Section: Introductionmentioning

confidence: 99%

Safety Evaluation of Plain Concrete Lining Considering Deterioration and Aerodynamic Effects

Wang

et al. 2023

Sustainability

Self Cite

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With an increase in the service time of high-speed railway tunnels, various defects caused by construction-quality defects in the secondary lining begin to appear. How to evaluate the safety of such tunnels and take countermeasures is very important for the safe operation of tunnels. Based on the load-structure method and a numerical simulation, this paper studied the short-term and long-term safety of the missing section of anti-crack reinforcement mesh in the plain concrete lining of a high-speed railway mountain tunnel. The short-term safety evaluation considered the influence of negative pressure caused by aerodynamic effects. The long-term safety evaluation considered the combined influence of the surrounding rock and concrete deterioration and the negative pressure and concrete fatigue damage caused by aerodynamic effects. The results showed that under the negative pressure generated by aerodynamic effects, the minimum tensile safety factor of the lining in the defective section increased by 3.8%, while the minimum compressive safety factor of the lining decreased by 7.9%. The negative pressure generated by the aerodynamic effects had little impact on the short-term safety of the lining in the defective section. During the long-term safety evaluation, the overall safety of the defective section decreased significantly, and the minimum tensile and minimum compressive safety factors of the lining decreased by 59.4% and 66.8%, respectively. The calculation results for the initial design do not meet the long-term design requirements and cannot guarantee the long-term safe operation of the tunnel. Finally, two new strengthening methods of galvanized steel mesh-short bolts and galvanized corrugated steel plate-short bolts were proposed to strengthen the defective section of the concrete lining, so as to improve the ultimate bearing capacity and toughness of the plain concrete lining structure.

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Mechanical Properties of GFRP Bolts and Its Application in Tunnel Face Reinforcement

Cited by 6 publications

References 24 publications

Stability Assessment of Tunnels Excavated in Loess with the Presence of Groundwater—A Case Study

Stability Assessment of Tunnels Excavated in Loess with the Presence of Groundwater—A Case Study

A Critical Review of Cold-Formed Steel Built-Up Composite Columns with Geopolymer Concrete Infill

Safety Evaluation of Plain Concrete Lining Considering Deterioration and Aerodynamic Effects

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