Simplified method for evaluating shield tunnel deformation due to adjacent excavation

Liang, Rongzhu; Wu, Wenbing; Feng, Yu; Jiang, Guosheng; Liu, Junwei

doi:10.1016/j.tust.2017.08.010

Cited by 151 publications

(84 citation statements)

References 24 publications

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“…e decrement in maximum horizontal displacement at monitoring point 1 of the tunnel structure with isolation pile reinforcement was defined as ΔS, as shown in equation (1). e reduction rate of the horizontal displacement difference between the tunnel structure roof and the floor was defined as β, as shown in equation (2):…”

Section: Influencing Factors Of Reinforcement Effects Of Isolation Pilesmentioning

confidence: 99%

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Reinforcement Effects of Isolation Piles on the Adjacent Existing Tunnel in Building Construction

Lü

Guo

et al. 2019

Advances in Materials Science and Engineering

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Similar material model test and numerical simulation method were used to study the reinforcement effect of isolation piles on the existing shield tunnel structure in the adjacent building construction for analyzing foundation pit excavation and new building construction approaching existing shield tunnel engineering. The numerical simulation orthogonal experiment was used to optimize four isolation pile parameters. The conclusions were obtained as follows: (1) Isolation piles could share horizontal load of the soil at the rear side of the support structure and reduce horizontal displacement of the soil. As a result, maximum horizontal displacement of the tunnel structure and differences in horizontal displacement between the tunnel structure roof and the floor after foundation pit excavation and building loading were decreased. The horizontal displacement and torsional deformation of the tunnel structure toward the direction of the foundation pit were controlled, and the increase in internal forces of the transverse tunnel structure was also restrained. (2) At the elevation above the tunnel roof, the increase in burial depth of the isolation pile top slightly affected the reinforcement effect on the tunnel structure. The increase in burial depth of the isolation pile bottom could improve the reinforcement effect. Thus, burial depth of the isolation pile bottom should be properly increased in the engineering practice. The reduction in pile spacing could improve the reinforcement effect. Accordingly, pile spacing should be properly selected in the engineering practice. With the increase of diameter of the isolation pile, the reinforcement effect of isolation piles increased obviously. (3) Pile diameter had the greatest influence on the reinforcement effect of isolation piles, followed by burial depth of the pile bottom, pile spacing, and burial depth of the pile top. Orthogonal experiments indicated the following optimal parameter values: a pile diameter of 1.2 m, a burial depth of the pile bottom of 2H, a pile spacing of 1.6 m, and a burial depth of the pile top of 0.75Z.

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Section: Influencing Factors Of Reinforcement Effects Of Isolation Pilesmentioning

confidence: 99%

“…Deformation and internal force of the tunnel structure are usually theoretically calculated using various methods, such as the Pasternak foundation model, semiempirical method, semianalytical method, singular function method, and Galerkin method [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Reinforcement Effects of Isolation Piles on the Adjacent Existing Tunnel in Building Construction

Lü

Guo

et al. 2019

Advances in Materials Science and Engineering

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“…If the induced tunnel deformation and internal forces exceed the capacity of the tunnel structures, segment cracking, leakage, and even longitudinal distortion of the railway track may occur and seriously threaten the smooth travel and safety of the trains in operation. Many studies have investigated the effects of adjacent excavation on existing shield tunnels using various methods, including in situ monitoring [1][2][3], centrifuge model tests [4][5][6], numerical analysis [7][8][9][10][11][12][13][14][15], and semi-analytical methods [16][17][18][19]. For example, the main objects of investigation have been the excavation dimension [13,15], relative distance between the tunnel and excavation [4,8,9,11,13], construction and reinforcement methods [10,12], tunnel dimension and physical parameters [9,13], soil density and wall stiffness [6], different constitutive models [14], and influence zone [20].…”

Section: Introductionmentioning

confidence: 99%

Effect of Soil Reinforcement on Tunnel Deformation as a Result of Stress Relief

Sun

2019

Applied Sciences

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Adjacent geotechnical engineering activities, such as deep excavation, may adversely affect or even damage adjacent tunnels. Ground reinforcement before excavation may be an effective approach to reduce tunnel heave as a result of stress relief. However, there are few quantitative studies on the effect of soil reinforcement on tunnel deformation. Moreover, the reinforcement mechanism of the reinforced soil and the reinforcement depth are not fully understood. In order to investigate the effect of reinforcing the ground on the tunnel response, a finite element analysis was conducted based on a previously reported centrifugal model test with no ground reinforcement. The effect of the Young's modulus and depth of the reinforced soil on tunnel deformation was analyzed. Soil stresses around the tunnel were also considered to explain the tunnel response. The results revealed that the Young's modulus of the reinforced soil and the reinforcement depth had a significant impact on tunnel deformation as a result of basement excavation. The tunnel heave in the longitudinal direction decreased by 18% and 27% for modulus of the reinforced soil, five times and ten times higher than that of the non-reinforced soil, respectively. The reinforcement depth was effective with regard to controlling the tunnel heave caused by stress relief. This is because the reinforced soil blocked the stress transfer and thus reduced the tunnel heave caused by excavation unloading. It is expected that this study will be useful with regard to taking effective measures and ensuring the safety and serviceability of existing metro tunnels during adjacent excavation.

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“…Ding et al [25] analyzed the law of soil displacement caused by shield tunnel construction of adjacent buildings. Liang et al [26] proposed a simplified analytical method to predict the shield tunnel behaviors associated with adjacent excavation by introducing the Pasternak foundation model with a modified subgrade modulus. Asano et al [27] presented an observational excavation control method for a mountain tunnel excavated adjacent to an existing tunnel in active service.…”

Section: Introductionmentioning

confidence: 99%

Influence Zone Division and Risk Assessment of Underwater Tunnel Adjacent Constructions

Zhou

Gao

Liu

et al. 2019

Mathematical Problems in Engineering

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Compared with ordinary tunnels, the influence analysis of underwater tunnel adjacent constructions is more complicated. At present, the empirical method used to divide the influence zone of the tunnel adjacent constructions has great uncertainty. So it is of great significance for actual construction and design to determine the influence zone accurately according to theoretical calculations. In this paper, based on the Hoek–Brown nonlinear failure criterion of rock mass and taking seepage factor into account, the stress state of rock mass around the underwater tunnel adjacent constructions can be deduced by elastoplastic theory. Then combined with the concept of “loose zone-bearing zone”, the influence zone division method of underwater tunnel adjacent constructions is proposed, and it is applied to the analysis of engineering examples. Through the deduced theoretical formulas, the influence zone of underwater tunnel adjacent construction can be divided into extensively strong, strong, relatively strong, weak, and noninfluence zones. Corresponding the influence zones with the risk levels in the code, different control measures are adopted for different risk levels, which can provide certain guidance for the design and construction of tunnel in practical engineering.

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Simplified method for evaluating shield tunnel deformation due to adjacent excavation

Cited by 151 publications

References 24 publications

Reinforcement Effects of Isolation Piles on the Adjacent Existing Tunnel in Building Construction

Reinforcement Effects of Isolation Piles on the Adjacent Existing Tunnel in Building Construction

Effect of Soil Reinforcement on Tunnel Deformation as a Result of Stress Relief

Influence Zone Division and Risk Assessment of Underwater Tunnel Adjacent Constructions

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