Face stability analysis of a shallow tunnel in the saturated and multilayered soils in short-term condition

Li, Pengfei; Wang, Fan; Zhang, Chengping; Li, Zheng

doi:10.1016/j.compgeo.2018.11.011

Cited by 72 publications

(9 citation statements)

References 44 publications

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“…(1) Interaction between cutter head and soil: some ground is lost in front of the cutter head of the EPB shield machine as it cuts and squeezes the soil [37][38][39][40]. e EPB shield machine cuts the soil according to the speed and torque of the cutter head.…”

Section: Influencementioning

confidence: 99%

Visualization of Multivariate Time‐Series Characteristics of Ground Loss Caused by Shield Tunneling

Rong

Gao

Wang

et al. 2021

Shock and Vibration

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Ground loss due to earth pressure balance shield tunneling eventually leads to a surface settlement which can be an issue of great concern. However, the existing machine learning methods ignore the continuous and dynamic nature of EPB shield tunneling. In this work, a multivariate time-series (MTS) model for ground loss is proposed based on an analysis of factors and processes related to ground loss combined with the characteristics of original time-series data involving multiple parameters recorded by EPB shield machines in real time. A method of visualizing MTS features based on a residual network and multichannel fully convolutional neural network is also presented. The validity of the proposed ground-loss model is verified via calculation and comparison with 13 EPB shield construction projects carried out in typical urban areas featuring soft soil. Thermal maps are thus obtained to visualize the classification contributions, which provide a visual basis for feature analysis.

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Section: Influencementioning

confidence: 99%

Visualization of Multivariate Time‐Series Characteristics of Ground Loss Caused by Shield Tunneling

Rong

Gao

Wang

et al. 2021

Shock and Vibration

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“…As shown in Figure 4, the construction loadings considered in this model from the excavation face until the shield tail are in sequence of the face pressure [36], the friction force between the shield skin and the ground, the jacking force and the grouting pressure [37][38][39].…”

Section: Modelling Of Construction Loadingsmentioning

confidence: 99%

Influence of Approaching Excavation on Adjacent Segments for Twin Tunnels

Zhang

et al. 2019

Applied Sciences

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This paper aims at influence analysis of approaching excavation on adjacent segments for twin tunnels with variable clear spacing located in Beijing, China. A series of numerical simulations have been conducted to investigate the influence of approaching excavation on ground displacements and mechanical responses of segments. What's more, on-site monitoring was conducted at the position of the minimum spacing between the twin tunnels. It is found that the deformation of the measured segment presents a pronounced asymmetric ovalization when the second tunnel approaches the measured cross-section. During the approaching excavation of the second tunnel, the normal force increases gradually, whereas the bending moment first decreases and then increases. The maximum increments of internal forces in the measured segment are both located at the regions near the second tunnel, in which the springline and shoulder of the segment are mainly subject to the effect of the circumferential compression and axial tension. The approaching excavation reduces the horizontal displacements of the ground between twin tunnels and increases the ground settlements as well as the horizontal displacements of the ground on both sides. The actual tunneling case of first along the curved trajectory and then along the straight-line trajectory can reduce internal forces of the segment.Liang et al. [10] obtained the unloading vertical stress field beneath the new tunnel based on Mindlin solutions [11]. Kong et al. [12] obtained the analytical solution of the displacement field of twin tunnels by using the Schwartz alternating theory. The ground settlements during the construction of twin tunnels were predicted by the experimental and numerical methods [1,[13][14][15]. The influence of the interaction between twin tunnels on the horizontal and vertical ground displacements will induce the variations of structural forces during the approaching excavation [16].The field measurement on the strain (or stress) increments in the segment induced by the approaching excavation were carried out by Gao et al. [9]. Unfortunately, comparative and parametric analyses have not been implemented via numerical or analytical methods [17][18][19][20][21]. The finite element modeling was performed to predict the influence of approaching excavation on the ground displacements and the structural forces in the segment of twin tunnels [22][23][24]. However, the construction loadings (e.g., friction force, jacking force, grouting pressure, etc.) were not simulated in detail. Note that the lateral spacing between twin tunnels in the above investigations is constant along the tunneling direction, while this condition of equal spacing is often subject to other factors and cannot meet in actual engineering.In this paper, twin tunnels with variable clear spacing is taken as a case study. The meticulously and completely real-time monitoring on the adjacent segment has been carried out. Furthermore, the influence of the tunnel approaching excavation on the internal forces of the...

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“…With the increasingly tense urban space, it is inevitable for an urban shield tunnel to cross under and side through the existing building structure. e disturbance impact on the surrounding building structure is a problem that must be considered in the shield construction of urban subway tunnel; aiming at the settlement disturbance analysis of surrounding buildings caused by shield construction of urban subway tunnel, scholars have analyzed such problems from the perspectives of construction monitoring [1][2][3], theoretical analysis [4][5][6][7][8], and numerical simulation [9][10][11][12][13]31]. ere are many related research results, most of which are lateral disturbance analysis of straight-line section shield, while there is less analysis on the disturbance of existing building structure caused by the construction of turning shield tunnel, the interaction mechanism between turning shield tunnel excavation and existing buildings is more complex, which is affected by turning radius, advance excavation volume, ground conditions, tunnel structural characteristics, relative space position between shield and tunnel, type of shield machine, shield construction parameters, and whole process [14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Measurement and Simulation Analysis of Vertical Cross Longitudinal Settlement between Turning Shield and Foundation Pit

Yin

Zhang

2021

Advances in Civil Engineering

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Using numerical simulation technology, the dynamic three-dimensional model of the turning shield and the foundation pit under the condition of vertical intersection is established. The disturbance law of the longitudinal settlement of the foundation pit under the condition of shield construction is studied, and the stress path in the soil is analyzed. The results show that with the gradual advance of the turning shield construction, the settlement mode of the foundation pit changes with the shield construction. During the construction of the turning shield, when the tunnel face is located in front of the foundation pit and under the foundation pit, the ground loss rate is inconsistent, which leads to the change of settlement mode. Under the influence of turning shield construction disturbance, the soil undergoes compression deformation caused by larger additional stress increase; after shield crossing, the soil undergoes unloading deformation caused by more obvious stress relaxation.

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Face stability analysis of a shallow tunnel in the saturated and multilayered soils in short-term condition

Cited by 72 publications

References 44 publications

Visualization of Multivariate Time‐Series Characteristics of Ground Loss Caused by Shield Tunneling

Visualization of Multivariate Time‐Series Characteristics of Ground Loss Caused by Shield Tunneling

Influence of Approaching Excavation on Adjacent Segments for Twin Tunnels

Measurement and Simulation Analysis of Vertical Cross Longitudinal Settlement between Turning Shield and Foundation Pit

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