Effects of above-crossing tunnelling on the existing shield tunnels

Liang, Rongzhu; Xia, Tao; Hong, Yi; Feng, Yu

doi:10.1016/j.tust.2016.05.002

Cited by 123 publications

(42 citation statements)

References 25 publications

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“…People are also exploring fast and low-cost evaluation methods while gaining an in-depth understanding of tunnel blasting vibration effects. Liang et al [15] studied the interaction mechanism between existing tunnels and proposed a simplified analysis and evaluation method to better understand and evaluate the impact of cross-tunneling on existing tunnels.…”

Section: Introductionmentioning

confidence: 99%

Influence of Small, Clear Distance Cross-Tunnel Blasting Excavation on Existing Tunnel below

Duan

Gong

et al. 2019

Advances in Civil Engineering

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The vibration effect generated during tunnel excavation can influence or damage adjacent tunnels. Studying and controlling the blasting vibration effect has important theoretical and practical significance, especially for new tunnels. This paper takes the tunnel project of Gao Jiu Lu-Jia Hua Cross Tunnel in Chongqing as the research background and assesses the blasting vibration influence in the up-down cross-tunnel. Onsite monitoring and numerical simulation were used to analyze peak particle velocity (PPV) changes, stress distribution, and crown settlement during the excavation process of Gao Jiu Lu I Tunnel at Jia Hua Tunnel Left Line in the cross-section. Influence laws of blasting excavation in a small, clear distance cross-tunnel on an existing tunnel below were obtained. Results show that new tunnel blasting vibrations exerted the largest influence on the crown of the existing tunnel below in the cross-section. The maximum tensile stress of the secondary lining of the existing tunnel below was mainly concentrated in the crown area. The maximum compressive stress during excavation was concentrated in the crown foot, and the stress value was less than the tensile and compressive strength of the concrete. The loosening of the surrounding rock from blasting excavation of the new tunnel caused secondary settlement of the existing tunnel crown below. The cumulative settlement value at the cross-section of the two tunnels was the largest. With an increase in axial distance from the cross-section of the existing tunnel crown, the settlement value gradually declined and became stable. These research results have reference value for the construction of a small, clear distance cross-tunnel and provide theoretical guidance for similar tunnel excavation projects in the future.

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Section: Introductionmentioning

confidence: 99%

Influence of Small, Clear Distance Cross-Tunnel Blasting Excavation on Existing Tunnel below

Duan

Gong

et al. 2019

Advances in Civil Engineering

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“…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.…”

Section: Introductionmentioning

confidence: 99%

“…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.…”

mentioning

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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“…Many previous studies examined the interaction between tunnels during construction of above-crossing tunnels by means of centrifugal and physical tests and the establishment of 3D FE models [21][22][23]. Liang [24] proposed a simplified analytical method for evaluating the behavior of underlying tunnels to obtain a better mechanical understanding of the above-crossing tunneling on the existing tunnels. Do et al [25] performed a series of 3D numerical analyses to investigate the influences of the constructions process on two parallel and stacked tunnels.…”

Section: Introductionmentioning

confidence: 99%

Effect of Expanding a Rectangular Tunnel on Adjacent Structures

Wang

Kong

Wang

2018

Advances in Civil Engineering

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e expansion of urban underpass has become the mainstream of development to cope with urban congestion, and the effect on adjacent existing structures during enlarging construction is also an important issue in the construction process. In order to better understand the influence of tunneling on adjacent structures, the pedestrian underpass expanding project above-crossing Xi'an Metro Line 1 was investigated. e aim was to analyze the deformation curves characteristics of adjacent structures by field observation of ground settlement, heave of existing tunnels, and settlement of piles. e results show that the ground settlement curve in the vertical direction of the underpass is similar to the shape of V, and the maximum settlement appearing in the center line of underpass is 18.7 mm. Due to the effect of existing tunnels on the ground deformation, the settlement curve in the parallel direction of the underpass is similar to the shape of M. Above-crossing tunneling would cause the existing tunnels to heave, and the heave mainly occurs in the range of −6 m to 12 m between the pedestrian tunnel face and the center line of each tunnel. e heave curve is similar to the shape of inverted U. e settlement of piles is linear with its axial stress and significantly affected by its location. e settlement curve of piles is similar to the shape of S in two dimensions. On the basis of deformation curves, this paper presents some equations to describe the shape of V, M, inverted U, and S, respectively, by the inverted Gaussian distribution curve, superimposed Gaussian distribution curve, Gaussian distribution curve, and arctangent function.

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Effects of above-crossing tunnelling on the existing shield tunnels

Cited by 123 publications

References 25 publications

Influence of Small, Clear Distance Cross-Tunnel Blasting Excavation on Existing Tunnel below

Influence of Small, Clear Distance Cross-Tunnel Blasting Excavation on Existing Tunnel below

Influence of Approaching Excavation on Adjacent Segments for Twin Tunnels

Effect of Expanding a Rectangular Tunnel on Adjacent Structures

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