Effect of Subway Excavation with Different Support Pressures on Existing Utility Tunnel in Xi’an Loess

Yang, Min; Li, Hongru; Li, Ning; Shuang-suo, Yang

doi:10.1155/2020/8818949

Cited by 10 publications

(8 citation statements)

References 21 publications

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“…The parameters for the grouting materials and lining are taken from the literature [34][35][36]. The density of the segment is 2500 kg/m 3 , Poisson's ratio is 0.3, modulus of elasticity is 34.5 GPa, stiffness reduction coefficient is 0.8, and shell unit is adopted; the shield shell of shield machine has a density of 7850 kg/m 3 , Poisson's ratio is 0.2, modulus of…”

Section: Calculation Parametersmentioning

confidence: 99%

Study on the Stability and Seepage Characteristics of Underwater Shield Tunnels under High Water Pressure Seepage

Chen,

Xi,

Dong

et al. 2023

Sustainability

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The construction of underwater shield tunnels under high water pressure conditions and seepage action will seriously impact the stability of the surrounding rock. In this study, an analytical model for the strength of the two-lane shield tunneling construction under anisotropic seepage conditions was established, and a series of simulations were carried out in the engineering background of the underwater section of Line 2 of the Taiyuan Metro in China, which passes through Yingze Lake. The results show that: (1) the surface settlement has a superposition effect, and the late consolidation and settlement of the soil body under seepage will affect the segment deformation and the monitoring should be strengthened; (2) under the influence of the weak permeability of the lining and grouting layers, the pore pressure on both sides of the tunnel arch girdle is reduced by about 72% compared with the initial value, with a larger hydraulic gradient and a 30% reduction at the top of the arch; (3) within a specific range, the tunneling pressure can be increased, and the grouting pressure and the thickness of grouting layer can be reduced to control the segment deformation; (4) the more significant the overlying water level is, the larger the maximum consolidation settlement and the influence range of surface settlement. This study can provide a reliable reference for underwater double-lane shield tunnel design and safety control.

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Section: Calculation Parametersmentioning

confidence: 99%

Study on the Stability and Seepage Characteristics of Underwater Shield Tunnels under High Water Pressure Seepage

Chen,

Xi,

Dong

et al. 2023

Sustainability

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show abstract

“…So far, there is no precedent for the construction of slotted shields in a loess tunnel. There is no systematic research on the application of a shield method in high-speed railway tunnels, and there is little experience that can be used for reference (Jiang et al, 2017;Yang, et al, 2020;Niu et al, 2021;Weng et al, 2021;Zhu, 2021;Mei et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Study on the construction deformation of a slotted shield in loess tunnels with different buried depths and large sections

Han

Fang

et al. 2023

Front. Earth Sci.

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Since there is no precedent for the use of slotted shield tunneling in the large section of high-speed railways in China, the relevant technological accumulation and systematic research achievements are few. Therefore, this paper provides theoretical support for loess tunnel construction decision-making through the study of slotted shields and is expected to promote the mechanization and even intelligent construction of a high-speed iron-loess tunnel. Taking the Luochuan tunnel of the Xiyan high-speed railway as the engineering background, this paper uses the numerical simulation software packages of ANSYS and FLAC3D to study the tunnel deformation (surface settlement, vault settlement, tunnel bottom uplift, and horizontal convergence) caused by the slotted shield construction in three different buried depths of 30, 40, and 50 m surrounding rock. The deformation law and mechanical characteristics of a cutter shield construction of large cross-section loess tunnels under the influence of different buried depths are put forward. Results showed that 1) the mutual interference between the working procedures can be significantly reduced by inserting the cutting tool into the soil instead of the advanced tubule before excavation; 2) the settlement in the upper part of the longitudinal axis of the tunnel is the largest; the greater the depth of the tunnel is, the smaller the surface settlement is; and 3) the horizontal deformation of the arch waist and foot of the tunnel under different buried depths is symmetrically distributed into the tunnel during the whole process of slotted shield tunneling.

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“…Wang and Jiang (2019) took the project of an underground utility tunnel in Beijing as an example to analyze and optimize the construction scheme of comprehensive utility tunnel passing through the existing subway. Yang et al (2020Yang et al ( , 2021 studied the interaction between subway and comprehensive tunnel in loess area.…”

Section: Introductionmentioning

confidence: 99%

Impact of subway shield tunnel construction on deformation of existing utility tunnel

Shi¹,

Zenglin²,

Min

et al. 2023

Front. Earth Sci.

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In recent years, the development of urban underground space in China, especially the construction and operation of subway tunnels, has greatly relieved the pressure of urban traffic. Due to the imperfect planning of urban facility, many subway tunnels have to be built under the existing utility tunnels (pipe galleries). Nevertheless, shield construction of subway tunnel has a great adverse impact on the deformation and safety of the existing pipe gallery. Therefore, this paper takes Xi’an Metro Line 2 as an example, and studies the safety depth for subway tunnel shield construction under different regional conditions in Xi’an through numerical simulation. The results show that the deformation of the existing pipe gallery and its influence range decrease with the rising buried depth of the double-line subway tunnel when the soil properties are good. For example, in the loess tableland area, when the buried depth of the subway tunnel is greater than 12 m, the settlement deformation of the pipe gallery basically meets the control standard. When the soil properties are poor or the soil properties vary greatly, the subway tunnel excavation has a great impact on the safety of the pipe gallery. For example, in the first-level alluvial fan area with sand layer, when the buried depth of the subway tunnel is less than 24 m and more than 12 m, the deformation standard cannot be satisfied. In addition, in the first-level alluvial fan area with sand layer, the lower soil layer should be treated or the construction parameters should be optimized before the excavation of subway tunnel. The research results can provide reference for similar engineering construction.

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Effect of Subway Excavation with Different Support Pressures on Existing Utility Tunnel in Xi’an Loess

Cited by 10 publications

References 21 publications

Study on the Stability and Seepage Characteristics of Underwater Shield Tunnels under High Water Pressure Seepage

Study on the Stability and Seepage Characteristics of Underwater Shield Tunnels under High Water Pressure Seepage

Study on the construction deformation of a slotted shield in loess tunnels with different buried depths and large sections

Impact of subway shield tunnel construction on deformation of existing utility tunnel

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