Load transferring mechanism of pipe umbrella support in shallow-buried tunnels

Zhang, Zhiqiang; Li, Huayun; Liu, Hongyan; Li, Guangjing; Shi, Xiaoquan

doi:10.1016/j.tust.2014.05.018

Cited by 40 publications

(13 citation statements)

References 5 publications

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“…At present, the main methods to increase initial support system are as follows: improved concrete strength [3][4][5][6]; encrypted steel arch [7,8]; and new arch structures [9,10]. Multistage layered support mainly includes advance pipe shed support [11,12] and double-layer initial support [13]. e above method improves the bearing capacity of the supporting structure, effectively controls the development of the plastic area, and alleviates the large deformation of the soft rock tunnel.…”

Section: Introductionmentioning

confidence: 99%

Effects of High‐Pretension Support System on Soft Rock Large Deformation of Perpendicularly Crossing Tunnels

Gan

Zhou

2020

Advances in Civil Engineering

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The control mechanism of prestressed support system is studied by means of three-dimensional discrete element numerical simulation, theoretical analysis, and field measurement. The actual project is selected to analyze, and the control effect is demonstrated. The theoretical analysis results show that the prestressed support can improve the self-bearing capacity of surrounding rock, which is conducive to the stability of the surrounding rock. The numerical calculation shows that, under the control of the long and short cables, the prestress can spread effectively and form two bearing arches. The deformation is difficult to control, which is in the arch crown and the arch shoulder of the tunnel intersection. However, the deformation of the surrounding rock decreases with the increase of prestress. Through the analysis of the measured results, it shows that the pretension support design scheme can effectively control the large deformation of the surrounding rock.

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Section: Introductionmentioning

confidence: 99%

Effects of High‐Pretension Support System on Soft Rock Large Deformation of Perpendicularly Crossing Tunnels

Gan

Zhou

2020

Advances in Civil Engineering

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“…The pipe-roofing method has advantages for underground construction in complicated geological conditions, especially in terms of restraining the ground settlement and reducing the engineering risk caused by excavations (Chen et al, 2019; Jiang et al, 2017). For the traditional pipe-roofing structure, the interlock devices with lower stiffness serve as the connections to make every steel tubes connected to form a complete supporting system (Wang and Jia, 2009; Xiao et al, 2016; Zhang et al, 2014). Because the transverse connections are unsubstantial, an intensive temporary supporting system was generally cooperated with pipe-roofing structure during tunneling (Jiang et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of the flexural mechanism and performance of channel steel tube slab structure under concentrated loads

Zhang

Zhao

Liu

et al. 2020

Advances in Structural Engineering

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Experimental studies about the flexural performance of channel steel tube slab (CSTS) structure subjected to concentrated loads were carried out, with considering various spacing of adjacent tubes, longitudinal spacing between the channel steel and missing tensile channel steel. A self-designed flexural device equipped with particle image velocimetry (PIV) technology was used to monitor continuous structure deformation and concrete cracking characteristics. In this study, the mechanism and performance of CSTS structure serving in underground engineering were analyzed, and a theoretical model for the bearing capacity of the CSTS structure was proposed. The results show that the failure mode of the test specimens exhibits ductile failure with an average ductility coefficient 2.52. The large shear strain of the concrete was obtained from PIV speckle contour, and it shows the same propagation trend compared with the main cracks appearing in the tests. In addition, the tensile channel steel along with decreasing the spacing of adjacent tubes can increase the bearing capacity of the specimens. The proposed theoretical model shows a reasonable prediction of the ultimate bearing capacity of specimens compared with the experimental results.

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“…Umbrella arches are identified as the most commonly used pre-supports in various engineering situations [10][11][12]. Pipe roofs and leading ductules are the two widely used types of the umbrella arches, applied in the construction of underground space under harsh geological conditions [13][14][15]. During the recent years, many studies have aimed to identify the mechanism behind these two types of pre-supports.…”

Section: Introductionmentioning

confidence: 99%

Displacement Characteristics of Shallow-Buried Large-Section Loess Tunnel with Different Types of Pre-Supports: A Case Study of New Badaling Tunnel

et al. 2019

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Three-bench seven-step excavation method (TSEM) has been widely used in large-section loess tunnels for high-speed railway in China. As the most commonly applied pre-supports, pipe roofs and leading ductules are broadly used in the ground reinforcement of loess tunnels. Their application is to ensure face stability and prevent tunnel collapse during construction. This study focused on the impacts of the TSEM on the ground surface settlement (GSS), as well as the tunnel displacement characteristics for the high-speed railway tunnels with large cross-sections in loess ground. Furthermore, the reinforcement effects of the two kinds of pre-supports were compared in this study. In-situ tests for a total of 12 sections were conducted to reveal the GSSs and displacement characteristics for the shallow-buried large-section loess tunnels. The monitoring results showed that the excavation process plays a significant role on the GSSs and tunnel displacements. A maximum value was observed for the tunnel displacement rate at the excavation of the upper and middle benches, where the face instability or collapse were prone to occur. The GSS trough curves were deviated to the early excavation side, with no conformation to the Gauss distribution. After a series of comparisons, we concluded that the pre-reinforcement effect of the pipe roof is better than that of the leading ductule for the loess tunnels.

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Load transferring mechanism of pipe umbrella support in shallow-buried tunnels

Cited by 40 publications

References 5 publications

Effects of High‐Pretension Support System on Soft Rock Large Deformation of Perpendicularly Crossing Tunnels

Effects of High‐Pretension Support System on Soft Rock Large Deformation of Perpendicularly Crossing Tunnels

Experimental investigation of the flexural mechanism and performance of channel steel tube slab structure under concentrated loads

Displacement Characteristics of Shallow-Buried Large-Section Loess Tunnel with Different Types of Pre-Supports: A Case Study of New Badaling Tunnel

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