Effects of pipe roof supports and the excavation method on the displacements above a tunnel face

Hisatake, Masayasu; Ohno, S.

doi:10.1016/j.tust.2007.02.002

Cited by 77 publications

(26 citation statements)

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“…Hisatake and Ohno [7] examined a large-scaled laboratory model to evaluate the performance of arming the above-tunnel parts and design process improvement. Their research shows that, when the forepole is used in sandy soil saturation, tunnel crown subsidence can be reduced; and the maximum subsidence of a drilled ground by arming the tunnel face through forepoles is equal to 1/4 soil subsidence in similar conditions and in conditions without using reinforcing methods.…”

Section: Check Out Of Some Of the Studies In The Field Of Umbrella Armentioning

confidence: 99%

The Types of Tunnels Maintenance in Umbrella Arch Method

Rostami

Dehkordi²,

Ziarati

et al. 2016

OJCE

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During tunneling in loose grounds, the ground deformation caused by drillings around the tunnel, leads to land subsidence and the adjacent tunnel which would affect tunnel structure and surrounding structures. In such situations it is necessary to improve the properties of the ground prior to drilling operations. In order to acquire tunnel face stability during excavation operations in areas with loose soil fault or areas with lack of adhesion, there are various methods such as split cross drilling, frame holder or auxiliary pre-holding methods such as umbrella arch method; preholding methods must provide safety when drilling and must be affordable, economically. In this study, we assessed the previous studies on methods and behaviors of umbrella arch strategy in reinforcing the concrete tunnels, reached the purpose with experimental and numerical methods and offered the latest design achievements, implementation progresses and analysis in relation with this method.

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Section: Check Out Of Some Of the Studies In The Field Of Umbrella Armentioning

confidence: 99%

The Types of Tunnels Maintenance in Umbrella Arch Method

Rostami

Dehkordi²,

Ziarati

et al. 2016

OJCE

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“…Adopting pipe-roofs is an effective measure extensively applied to overcome the poor stability and slope sliding of heading [4][5][6][7]. Many scholars have conducted extensive research on the support mechanism of pipe-roofs, including analytical studies [8][9][10][11], field tests [8,[12][13][14], numerical simulations [15][16][17][18], and model tests [19][20][21][22]. Existing work is mainly aimed at studying the mechanical behaviors of piperoofs in tunnel entry portals.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Pipe‐Roof in Tunnel Exiting Portal by the Foundation Elastic Model

Luo

Chen

Bao³

et al. 2017

Mathematical Problems in Engineering

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The Pasternak double-parameter elastic foundation model of pipe-roof during the construction of tunnel exits is first established. Based on the portal project of Hanjiashan highway tunnel, an inclinometer is adopted to measure the settlement deformation of a pipe-roof and demonstrates the deformation law in tunnel exiting portals. The formulas for calculating the deflection and internal forces are derived to analyze the deformation of the pipe-roof in each excavation stage, and the results are compared with field monitoring data. Finally, the influences of excavation height, excavation footage, and stiffness of the pipe-roof on the support effect are investigated. Analysis indicates that the longitudinal settlement curve shows a groove distribution, which can be divided into five stages: micro, rapid, continuous, resilience, and stable deformation. Moreover, the subsidence rate reaches its maximum at the tunnel face. The influence of tunnel excavation on the deformation mainly has a range of 1.5 times the excavation height. To control the deflection of the pipe-roof, excavation height should be controlled in the range of 3.5 m, excavation footage should be controlled in the range of 1-1.4 m, and the diameter and thickness of the selected pipe-roof should be in the ranges of 89-159 mm and 5-8 mm, respectively.

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“…Therefore, the analytical and the experimental demonstrations that take the above-mentioned factors into account are very important in terms of knowing the mechanisms of the ground around the tunnel face. On the other hand, centrifugal model experiments (Hisatake and Ohno, 2008), which employ the ringcut excavation method with pipe roof supports, have been conducted for such grounds. According to the results, the effect of the ring-cut excavation method in decreasing the subsidence of the ground ahead of the face is much more remarkable than that of the full-face excavation method.…”

Section: Introductionmentioning

confidence: 99%

“…Mair et al (1981) used internal support to tunnels which was provided by compressed air within a rubber bag, and the compressed air was reduced under the centrifuge acceleration at the pre-determined value. In the present experiments, the tunnel excavation is realized through the use of a three-dimensional excavation robot which can excavate the ground by computer programs in an arbitrary shape under the centrifugal field (Hisatake and Ohno, 2008 In addition, three-dimensional elasto-plastic finite element analyses, corresponding to the model experiments, are simultaneously conducted. Considerations are given to the mechanical conditions by comparing the results of the experiments with those of the analyses.…”

Section: Introductionmentioning

confidence: 99%