Experimental study of the coupling effect on segmental shield tunnel lining under surcharge loading and excavation unloading

Zhang, Jinzhang; Huang, Hongwei; Zhang, Dongming; Phoon, Kok Kwang

doi:10.1016/j.tust.2023.105199

Cited by 20 publications

(7 citation statements)

References 45 publications

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“…where N cu is the ultimate bearing capacity of the normal section (kN), the definitions and values of α 1 and β are the same as those in reference [49], ξ is the relative compression zone height, x is the height of the concrete compression zone (mm), and σ s is the stress of a tensile steel bar under small eccentric compression (kPa). When it is determined to be large eccentric compression, the bearing capacity of the normal section is calculated using Equations ( 11) and (13). When it is determined to be small eccentric compression, the bearing capacity of the normal section is calculated using Equations ( 12)-( 14).…”

Section: Ultimate Bearing Capacitymentioning

confidence: 99%

“…Therefore, it is very important to study the mechanical response characteristics of the shield segment under surcharge loading and evaluate its safety performance to maintain the normal operation of the shield tunnel [3]. Currently, scholars have conducted a series of studies on the mechanical response and deformation mechanism of shield tunnel lining structures under surcharge loading using various research methods, including theoretical analysis [4][5][6], numerical simulation [7][8][9], field measurements [10][11][12], and model tests [13][14][15][16]. Among these methods, numerical models have been favored by researchers due to their ability to conveniently calculate the mechanical response characteristics of shield tunnel structures under various loading conditions.…”

Section: Introductionmentioning

confidence: 99%

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Comparative Analysis and Safety Evaluation of Shield Segment Structure Model under Surcharge Loading

Liu,

Jiang,

et al. 2023

Materials

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In shield tunneling projects, the selection of an accurate model to calculate the mechanical response of segment structure plays a crucial role in the design and cost of the project. The shell–spring and beam–spring models are two widely used methods for this purpose. However, it is still not clear how accurate and different these models are in calculation results under surcharge load. Therefore, to accurately calculate the internal forces and deformation of the segment structure and clarify the difference between the two models’ results, the shell–spring and beam–spring models were established based on a subway shield tunnel project in Zhengzhou city. The reliability of the models was verified by comparing and analyzing the differences in deformation results between the models and field measurements. Furthermore, the safety of the segment structure was evaluated according to the ultimate bearing capacity of the normal section. The results declare that: (1) In the shell–spring model, the internal force gradually reduces from the edges towards the center of the segment width, and the shield segment exhibits a prominent non-plane strain state. (2) The internal force of the beam–spring model is larger than that of the shell–spring model. The axial force difference between the two models is relatively small; meanwhile, there is a larger disparity in the bending moment. However, with an increase in surcharge loading, the discrepancy in internal forces between the two models gradually decreases. (3) The calculation results of the shell–spring model are close to the field-measured values and the shield tunnel model test values, which verifies the accuracy and reliability of the shell–spring model. Therefore, it is more reasonable to use the shell–spring model to calculate the mechanical response of the segment structure. (4) With an increase in surcharge loading, the safety of the shield tunnel decreases gradually. Therefore, surcharge loading above the shield tunnel should be reasonably controlled to meet the requirements of the normal use of the shield segment. This manuscript aims to provide a reference for the future design and optimization of the shield tunnels’ lining structure.

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Section: Ultimate Bearing Capacitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparative Analysis and Safety Evaluation of Shield Segment Structure Model under Surcharge Loading

Liu,

Jiang,

et al. 2023

Materials

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“…Most of the topsoil in Yangshan port is soft clay [56], and there is sand soil in the lower layer. Through the geological investigation, the site of Yangshan Port consists of four typical soil layers: clay layer, silty clay layer, muddy silty clay, and sand soil layer.…”

Section: Calculation Model and Parameters Of Soil Layermentioning

confidence: 99%

Effect of Soil Anisotropy on Ground Motion Characteristics

Xie,

Cao,

2023

Buildings

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Soil transverse isotropy results in different stiffness characteristics in horizontal and vertical directions. However, the effect is usually neglected in seismic motion analysis. In this study, an equivalent linear anisotropic soil model was established based on the finite element method, and we investigated the impact of anisotropic parameters on ground motion at the site under various seismic wave inputs. It was found that the anisotropic parameters have a more significant effect on seismic waves, with the dominant frequency being closer to the fundamental frequency of the site. As an example, the soil dynamic parameters in Shanghai Yangshan Port were calibrated by a series of bending elements, resonance columns, and cyclic triaxial tests. The influences of anisotropy on the peak ground acceleration (PGA) and response spectrum were studied for Yangshan Port. Additionally, the standard design response spectra considering the soil anisotropy were provided. A comparison reveals that the existing isotropic design response spectrum may lead to dangerous seismic design for the structures at Yangshan port.

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“…There is also a growing demand for a thorough evaluation of key design parameters [22]. On the other hand, it is worth noting that an increasing number of constructed tunnels are now exposed to environmental disturbances, such as ground surface surcharge [23,24], lateral unloading [25], top unloading [26], and adjacent construction activities [27,28]. Hence, an applicable numerical model can assist operators with evaluating structural performance when confronted with such emergencies.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Theoretical Investigations of the Mechanical Behavior of Column-Free Quasi-Rectangular Segmental Tunnel Linings

Liu,

Chen,

et al. 2024

Applied Sciences

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To investigate the mechanical behavior and design methodology of column-free QRST (quasi-rectangular segmental tunnel) structures, a theoretical analysis based on prototype experiments and simulation models is conducted. Initially, a prototype experimental investigation is conducted to reveal the structural behavior at the service stage. Subsequently, the ESHR model (Equivalent Stiffness Homogeneous Ring), the BS model (Beam Spring), and the MBS model (Modified Beam Spring) are used to simulate structural behavior. For design purposes, the design methodology is explored based on the ESHR model, followed by a sensitivity analysis of several key load parameters. Based on the experimental results, weak parts of the column-free QRST structure are found to include several joints (Joint 1, Joint 5, Joint 3, and Joint 8), and corresponding optimization measures are proposed. By comparing the test results, the above-mentioned three models demonstrate their applicability in structural simulation, with the ESHR model having sufficient design accuracy. A model-based deformation mechanism analysis found that joints contribute approximately 2/3 of the structural deformation. For the structural design of the column-free QRST using the ESHR model, amplifying the calculated results of structures directly subjected to the service stage by 10% suffices to meet engineering requirements. Based on the test and study, special attention should be paid to the negative bending moment regions at the waists of the structure during both the design and service stages.

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Experimental study of the coupling effect on segmental shield tunnel lining under surcharge loading and excavation unloading

Cited by 20 publications

References 45 publications

Comparative Analysis and Safety Evaluation of Shield Segment Structure Model under Surcharge Loading

Comparative Analysis and Safety Evaluation of Shield Segment Structure Model under Surcharge Loading

Effect of Soil Anisotropy on Ground Motion Characteristics

Experimental and Theoretical Investigations of the Mechanical Behavior of Column-Free Quasi-Rectangular Segmental Tunnel Linings

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