Behaviors of existing twin subway tunnels due to new subway station excavation below in close vicinity

Zhang, Chengping; Xu, Zhimin; Fang, Qian

doi:10.1016/j.tust.2018.07.020

Cited by 34 publications

(17 citation statements)

References 3 publications

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“…Thus, Figure 24a shows rather complete monitoring data, whereas Figure 24b-d only shows the relative displacements of the surrounding rocks following excavation. It is clear from Figure 24 that the critical stage affecting the deformation of slope and surrounding rocks was the approaching phase of the tunnel face [21]. All the monitored values were lower than the corresponding simulations, of which the slope stability deformation monitoring value was about 20% lower than the simulated value, and the final stability deformation monitoring values of the tunnel surrounding rocks were all lower than the upper limits (15 mm and 20 mm) for tunnel deformation stipulated by the Land Transport Authority (2000) and Building Department (2009) [9].…”

Section: Comparative Analysis Of the In Situ Monitoring Resultsmentioning

confidence: 99%

Numerical Parametric Study of Countermeasures to Alleviate the Tunnel Excavation Effects on an Existing Tunnel in a Shallow-Buried Environment near a Slope

et al. 2020

Applied Sciences

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This paper studies the influence law of existing tunnels on the construction of intersecting new tunnels in a shallow slope burial context through 3D numerical analysis. The emphasis is on exploring the effect of new tunnels constructed in 54 conditions, including three ratios of overburden to tunnel height (C/H), three ratios of slope distance to tunnel span (D/W), two backfilling conditions of the existing tunnel (“hty” and “htn” conditions), and three magnitudes of surface loads (10 kPa, 20 kPa, and 30 kPa), on the deformation of lateral slopes and the overlying road. As the results show, the rigidly separated area between the existing and newly built tunnels in parallel to the excavation direction was precisely the sensitive area affected by the existing tunnel backfilling condition. The road settlement simulations perpendicular to the excavation direction revealed that various C/H and D/W ratio combinations controlled the shape and size differences of the settlement trough curve. This was because the C/H ratio primarily controlled the effective span and height transition of the newly built tunnel, whereas the D/W ratio mainly controlled the intersection position of the tunnels. Next, model A-A (“hty” condition) was identified as the only feasible construction model among all models in accordance with the engineering safety control criteria. Lastly, comparison of monitoring data with simulations found a slight difference in the distribution pattern between the two. Nevertheless, the final maximum settlement fully satisfied the construction control requirements overall. Aside from proving the correctness of simulation results, the present study also sets an excellent referential example for similar projects.

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Section: Comparative Analysis Of the In Situ Monitoring Resultsmentioning

confidence: 99%

Numerical Parametric Study of Countermeasures to Alleviate the Tunnel Excavation Effects on an Existing Tunnel in a Shallow-Buried Environment near a Slope

et al. 2020

Applied Sciences

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“…According to the inspection results of double-arch tunnels in Sichuan and Chongqing, the depth or height of voids behind the lining generally ranged from 0.15 to 0.50 m, and the maximum value reached 1.09 m [19]. In practical engineering, field monitoring remains a generally recognized approach for understanding the deformation of the ground and the neighboring structures [20][21][22], whereas there are numerous voids with different sizes developed around the double-arch tunnel lining. Different arrangements and sizes of voids can change stress, deformation, and failure of the lining.…”

Section: Numerical Schemesmentioning

confidence: 99%

Effect of Voids Behind Lining on the Failure Behavior of Symmetrical Double-Arch Tunnels

Min

et al. 2019

Symmetry

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The presence of voids behind lining seriously affects the safety of the symmetrical double-arch tunnels during service life. It is essential to find out the impact of voids on tunnel safety due to the increasing demand for the construction and maintenance of symmetrical double-arch tunnels. Model tests and numerical analyses were conducted in this research. The results attained were explored including earth pressure, internal force, and lining failure. Results reveal that the presence of voids has a large influence on the internal force in the lining of symmetrical double-arch tunnels, generally in the form of asymmetrical failure patterns of the lining. The failure patterns of the lining are greatly influenced by the size and location of voids with respect to the symmetrical double-arch tunnel circumference. Significant changes in the lining internal forces were found at the areas in the close vicinity of the void whereas a few changes were found at the bottom of the sidewall, the invert, and the central wall far away from the void. The propagation laws of lining cracks of asymmetrical double-arch tunnels are more complicated than symmetrical tunnels with a void behind the central wall. The location of the initial cracking of symmetrical and asymmetrical double-arch tunnels is the same, while the lining failure of the large-section tunnel is the most complicated.

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“…In recent years, the safety of tunnel construction, especially the stability of the tunnel face [1][2][3][4] and the deformation of the ground and neighboring structures [5,6], has been a research hotspot in the field of tunnel engineering. With the large-scale expansion of the Chinese Railway Network, the problems of tunnel structure damage continue to arise.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Behavior of Tunnel Lining with Cracks at Different Positions

Jie

Niu

et al. 2020

Symmetry

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Cracks in the lining significantly reduce the safety of a tunnel during operation. It is urgent to figure out the influence of cracks on tunnel carrying capacity. In this paper, three-dimensional model tests were conducted to investigate deformation, internal force, and deterioration laws of the lining with prefabricated cracks at different positions. The main conclusions were obtained as follows: (1) The carrying capacity of the lining structure with prefabricated cracks was reduced, and the deformation of the lining structure increased. The penetration of the vault crown crack accelerated the damage of the lining structure, and structural failure occurred when the crack went through at the left arch spring. (2) The internal force of the lining was greatly affected by the positions of prefabricated cracks. The internal forces of the lining structure decreased with the existence of prefabricated cracks. Whether or not there were prefabricated cracks, tension cracks appeared in the inside fiber of the vault and inverted arch. (3) The deformation of the lining structure with the existence of prefabricated cracks increased. When the prefabricated crack was located at the vault, the deformation was the largest, followed by the arch spring, side wall, and arch shoulder. (4) The analysis shows that prefabricated cracks at the vault are the most damaging under stress and deformation of the lining structure, so longitudinal cracks at the vault should be strengthened.

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Behaviors of existing twin subway tunnels due to new subway station excavation below in close vicinity

Cited by 34 publications

References 3 publications

Numerical Parametric Study of Countermeasures to Alleviate the Tunnel Excavation Effects on an Existing Tunnel in a Shallow-Buried Environment near a Slope

Numerical Parametric Study of Countermeasures to Alleviate the Tunnel Excavation Effects on an Existing Tunnel in a Shallow-Buried Environment near a Slope

Effect of Voids Behind Lining on the Failure Behavior of Symmetrical Double-Arch Tunnels

Mechanical Behavior of Tunnel Lining with Cracks at Different Positions

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