Analysis of mechanical behavior in a pipe roof during excavation of a shallow bias tunnel in loose deposits

Xiao, Jun; Dai, Fuchu; Wei, Yingqi; Xing, Yanfei; Cai, Hong; Xu, Chong

doi:10.1007/s12665-015-5176-y

Cited by 33 publications

(10 citation statements)

References 19 publications

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“…Researchers have also studied the settlement through model tests [16,17] and field monitoring [18][19][20][21][22], which increases the experience in various regions and is of guiding importance when tunnelling in similar strata. Regarding the auxiliary measures to confine settlement induced by metro tunnelling, there are three main aspects: grouting [23][24][25][26][27][28], pipe roof [29][30][31][32][33][34][35], and optimizing support parameters [36][37][38][39][40]. However, although the technology on STM comes a long way, it is still difficult to guarantee construction safety under all conditions.…”

Section: Introductionmentioning

confidence: 99%

Tunnelling‐Induced Settlement and Treatment Techniques for a Loess Metro in Xi’an

Lai

et al. 2020

Advances in Civil Engineering

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Techniques including pre-grouting, long pipe roof, and parameter optimization were employed to ensure the safety of loess metro tunnelling under an existing glass building. Their effects were proved through monitoring the settlement of building and surface during tunnelling. Besides, division of settlement monitoring according to processes, a new method, was conducted to control settlement in time. The highest surface settlement after construction was 16 mm only, meeting the requirement. The result indicates that it is practicable to control the tunnelling settlement strictly in extremely difficult geological areas. The settlement regularities were also studied through numerical simulation; their deformation is larger compared with in situ results while their change trends coincide during most processes. Soil excavations cause settlement primarily, accounting for more than 60%. It is suggested that dual slurry pre-grouting and process-based measurement should be employed before each excavation in water-rich loess areas.

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Section: Introductionmentioning

confidence: 99%

Tunnelling‐Induced Settlement and Treatment Techniques for a Loess Metro in Xi’an

Lai

et al. 2020

Advances in Civil Engineering

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“…One is that the grouting hole itself is easily blocked by gravel during drilling; the other is that the formation itself is dense and mud content is high, the gravel cannot be discharged during drilling pipe, and fine sand is mixed with mud to form a compact inclusion layer around the rod body. e liquid is difficult to penetrate [38].…”

Section: Grouting Difficultymentioning

confidence: 99%

New Construction Technology of a Shallow Tunnel in Boulder‐Cobble Mixed Grounds

Liu

Zhong

Feng

et al. 2020

Advances in Civil Engineering

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As a typical granular bulk medium, problems are common in boulder-cobble mixed grounds, such as easy collapse and instability and difficult effective support for large-section tunnel excavation. Tunnels constructed in BCM grounds are rare still, and there is a big gap between the design and construction of tunnels. Based on the Nianggaicun highway tunnel crossing the BCM grounds, the construction technology of tunnel in BCM grounds is studied by means of literature investigation and field survey. Here are the main conclusions: the overall deformation of surrounding rock is quite small; the pressure distribution of surrounding rock is small and loose pressure is dominant, and the safety reserve of secondary lining is large. The deformation process of surrounding rock concentrates on the construction stage. During the construction process, there are many problems, such as serious overexcavation, difficulty of bolt penetration, and continuous rock fall. In this paper, a three-bench complementary cyclic excavation method is proposed, which replaces the original CD and CRD methods. Meanwhile, the supporting system is optimized. The results show that the disturbance of surrounding rock is reduced, while the safety of construction process and the reliability of structure are increased. The new excavation method and optimized supporting system are expected to fill the gap between design and construction of tunnel in BCM grounds and provide reference for construction of such tunnels in the future.

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“…The development in highway tunnel construction demands the excavation of tunnels through mountain areas. The rugged landscape in those areas leads to the inevitable existence and rapid development of bias tunnels [1,2]. Due to their special form of load, bias tunnels are clearly distinguished from common tunnels in design and support [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study on Relaxed Surrounding Rock Pressure on Shallow Bias Neighborhood Tunnels under Seismic Load

Liu

Xiong

Liu

et al. 2021

Period. Polytech. Civil Eng.

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To study the distribution of relaxed surrounding rock pressure on the shallow bias neighborhood tunnels under the combined action of horizontal and vertical earthquake force, finite element software was used for failure mode analysis. Moreover, with the pseudo-static method, the calculation formula for the relaxed pressure on the shallow bias neighborhood tunnels was derived and used to analyze the variation of the rupture angle of these tunnels under the action of the seismic force. The study shows that: shallow bias neighborhood tunnels basically follow a “W” failure pattern under the combined action of horizontal and vertical seismic force, and the failure scope of the surrounding rock is controlled by four rupture angles. Rupture angles β2 and β3 between the deep and shallow tunnels of the shallow bias neighborhood tunnels are not affected by the surface slope. For tunnels with the same grade of the surrounding rock, the greater the seismic intensity, the smaller the value of β2, and the greater the value of β3. While at the same seismic intensity, the higher the grade of the surrounding rock, the smaller the β2 and β3. Ruptures angles β1 and β4 are influenced by the surface slope, seismic intensity and surrounding rock grades. A steeper surface slope leads to a smaller β1 and a greater β4; β1 increase and β4 decrease with increasing seismic intensity; while, β1 and β4 both show a decreasing trend with an increasing rock grade.

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Analysis of mechanical behavior in a pipe roof during excavation of a shallow bias tunnel in loose deposits

Cited by 33 publications

References 19 publications

Tunnelling‐Induced Settlement and Treatment Techniques for a Loess Metro in Xi’an

Tunnelling‐Induced Settlement and Treatment Techniques for a Loess Metro in Xi’an

New Construction Technology of a Shallow Tunnel in Boulder‐Cobble Mixed Grounds

Theoretical Study on Relaxed Surrounding Rock Pressure on Shallow Bias Neighborhood Tunnels under Seismic Load

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