Challenges and countermeasures for using pile-beam-arch approach to enlarge large-diameter shield tunnel to subway station

Xu, Xuezhao; Li, Zhaoping; Fang, Qian; Zheng, Hao

doi:10.1016/j.tust.2020.103326

Cited by 24 publications

(7 citation statements)

References 15 publications

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“…Liu [16] based on the PBA method of an underground station in Beijing, put forward the settlement and other parameter control standards of the project through numerical simulation combined with the on-site monitoring method. Xu [17] presented the monitoring data of the initial PBA method in China, demonstrating that the maximum surface settlements observed across different monitoring sections were not uniform. The author concluded that surface settlement was primarily attributable to the construction of the shield tunnel, the side guideway, and the middle guideway.…”

Section: Introductionmentioning

confidence: 99%

Optimization Study on Key Technology of Improved Arch Cover Method Construction for Underground Metro Stations Based on Similar Model Test

Yang,

Xu,

Peng

et al. 2024

Applied Sciences

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To enhance comprehension of the improved arch cover construction method for underground metro stations and provide guidance for future construction techniques and programs, the paper examines the indoor improved arch cover method of construction in the underground concealed excavation station of Tianhe Road Station of Guangzhou Metro Line 10, China. It includes a similar model test of the key technology and an analysis of the evolution law of the surrounding rock stress, the law of the ground settlement, and the law of the arch top deformation after the tunnel excavation. The study found that increased over-support can decrease arch settlement, with the maximum settlement occurring near the arch. Ground settlement typically occurs in the same areas as arch settlement, but arch settlement may occur earlier. The excavation of the arch cover has little impact on the overlying soil pressure, and the supporting structure is more effective in controlling soil deformation. The upper part of the arch cap experiences mainly extrusion stress, with the maximum stress occurring near the middle of the arch. The stresses in the arch’s base decrease significantly during the excavation of the side drifts but show an increasing trend during the excavation of the lower rock mass. The presence of the central column significantly affects both the settlement of the arch and the ground, as it bears most of the compressive stress of the arch. This stress decreases initially and then increases. The amplitude of deformation is more pronounced when the dismantled central column is closer to the middle of the arch.

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Section: Introductionmentioning

confidence: 99%

Optimization Study on Key Technology of Improved Arch Cover Method Construction for Underground Metro Stations Based on Similar Model Test

Yang,

Xu,

Peng

et al. 2024

Applied Sciences

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“…Consequently, constant improvements in construction methods and the emergence of new technical solutions have facilitated the expansion of many domestic underground projects (Song et al, 2020b;Huang et al, 2021). In particular, the expansion of subway stations through the addition of new superstructures to existing underground structures has proven economically advantageous (Xu et al, 2020;Liu et al, 2022). However, in the case of such expansion projects, large-scale excavation and the consequent unloading significantly impacts the existing subway structure.…”

Section: Introductionmentioning

confidence: 99%

Mechanical response and parametric analysis of a deep excavation structure overlying an existing subway station: A case study of the Beijing subway station expansion

et al. 2023

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The existing Beijing Pingguoyuan Subway Station was extended through a extension project. The excavation for the extension was located directly above the existing station. Complex interactions exist between the existing structure and the retaining pile wall of the excavation. Based on this project, three-dimensional finite element models were established to investigate the mechanical characteristics of the embedded and non-embedded retaining pile walls. A parametric analysis was performed for both types of pile walls. The stress and deformation characteristics of the retaining pile walls and existing structures were analyzed. The results show that when the bottom of the non-embedded retaining pile walls are connected to the existing structure, the uplift of the existing structure is essentially constant; however, the maximum displacement of the pile is increased by approximately 2.7 times, and the bending moment of the pile is reduced to 57.1% of the connection condition. As the distance between the embedded retaining pile wall and the existing station increases, the uplift of the existing station increases linearly, whereas the soil between the pile and the station exhibits a non-linear increasing trend. The displacement of the embedded retaining pile wall increases as the inner force decreases. When the distance is greater than 4.7 m, the displacement and force of the pile remains essentially unchanged. The effect of the pile embedded depth on the force and deformation of the pile is mainly observed in the lower part of the pile. As the embedded depth increases, the maximum displacement decreases by approximately 16.9%, the maximum bending moment decreases, and the maximum negative bending moment increases. The key contribution of this research is to provide a prediction method for the mechanical behaviors of a expansion project. The findings from the study also provide industry practitioners with a comprehensive guide regarding the specific applications of the construction technology of a deep excavation structure overlying an existing subway station.

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“…Xu X and others carried out relevant research on PBA construction method relying on Beijing metro line 14. The eld monitoring data show that the surface settlement is mainly caused by the construction of side pilot tunnel and middle pilot tunnel (Xu X et al 2020). Yang Zixuan and others, relying on the West Extension tunnel of Beijing Metro underpass the existing line 5, optimized the construction scheme of PBA method through numerical simulation, and proposed that pouring the second lining buckle arch after excavating 1 / 4 of the total length of the tunnel in the middle pilot tunnel can effectively control the surface settlement (Yang Zixuan et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Optimization of PBA construction process in Xinfadi-caoqiao section of Beijing Metro Line 19

Cui

Bohan

2022

Preprint

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The safety of subway tunnel construction using the PBA construction is the focus of attention at present. In this paper, based on the underground excavation project of Xin-cao section of Beijing Metro Line 19, the PBA construction process is studied by numerical simulation. The influence laws of surface settlement, structural deformation and internal force change after six construction procedures are compared and analyzed. The research results show that: after the excavation of small pilot tunnel, the extreme value of pavement settlement appears above the secondary lining vault, and the extreme value of safety factor of primary support structure of small pilot tunnel appears in the middle and both sides of the pilot tunnel vault; in order to ensure the construction safety, considering the displacement and internal force, it is suggested to excavate the middle pilot tunnel first, then construct the pile crown beam, and then excavate the two sides of the pilot tunnel Compared with other working conditions, this working condition can effectively control the pavement settlement and structural deformation, and the structural safety factor is the largest. The research results can provide a reference for the excavation of shallow buried multi pilot tunnel with tunnel pile-beam-arch approach.

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Challenges and countermeasures for using pile-beam-arch approach to enlarge large-diameter shield tunnel to subway station

Cited by 24 publications

References 15 publications

Optimization Study on Key Technology of Improved Arch Cover Method Construction for Underground Metro Stations Based on Similar Model Test

Optimization Study on Key Technology of Improved Arch Cover Method Construction for Underground Metro Stations Based on Similar Model Test

Mechanical response and parametric analysis of a deep excavation structure overlying an existing subway station: A case study of the Beijing subway station expansion

Optimization of PBA construction process in Xinfadi-caoqiao section of Beijing Metro Line 19

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