Centrifuge modelling of tunnelling induced ground displacements: pressure and displacement control tunnels

Song, Geyang; Marshall, Alec M.

doi:10.1016/j.tust.2020.103461

Cited by 29 publications

(26 citation statements)

References 28 publications

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“…The centrifuge strong box used for testing had internal dimensions of 150 mm width, 700 mm length, and a height of either 400 mm (TPSI1 and TPSI2) or 700 mm (TPSI3; a modified strongbox was used for this test). An eccentric rigid boundary mechanical (eRBM) model tunnel was used (Song et al, 2018;Song and Marshall, 2020) to simulate tunnel volume loss. The model tunnel contains a single bi-directional screw shaft with two hexagonal wedge-shaped shafts (fixed into the bi-directional ball screw flange nuts) that control the position of six segments that form the tunnel boundary.…”

Section: Centrifuge Modelmentioning

confidence: 99%

“…The two wedged-shaped shafts have six surfaces, with taper angle varying from 4°at the tunnel crown to 0°at the tunnel invert, creating an eccentric ground loss distribution around the tunnel (ground loss displacements decreasing from crown to invert). A detailed description of the model tunnel configuration is provided in Song et al (2018); Song and Marshall (2020). The model tunnel has an initial diameter of = 90 mm and was buried with a cover of = 162 mm, giving / = 1.8.…”

Section: Centrifuge Modelmentioning

confidence: 99%

“…Figure 8 shows the average shear stress ( ) versus the estimated radial effective stress ( ) after centrifuge spin-up for all piles in all five tests. The critical state line was plotted based on = 31.4°, which was obtained by performing dry heap tests and triaxial tests with the sand (Song and Marshall, 2020). As previously indicated, negative shear stresses developed along the piles after centrifuge spin-up (the soil settled more than the piles).…”

Section: Pile Load Distribution During Centrifuge Spin-upmentioning

confidence: 99%

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Centrifuge Study on the Influence of Tunnel Excavation on Piles in Sand

Song

Marshall

2020

J. Geotech. Geoenviron. Eng.

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Tunnelling induced ground movements can affect the equilibrium state of an existing pile, causing uneven settlement among pile groups and damage to connected structures. This paper presents results from five centrifuge tests aimed at evaluating the load redistribution mechanisms that occur within piles located close to tunnel excavation. Two main mechanisms are studied: firstly, those related to ground displacements and stress relief related to tunnelling; and secondly, those related to pile head load changes caused by connected superstructures (accomplished using a hybrid centrifuge-numerical modelling method). A novel fibre Bragg grating sensor system was used to measure shaft shear stresses along model piles. Results are used to quantify the relative impact that these two mechanisms have on pile load redistribution during tunnel volume loss. In addition, post-tunnelling pile loading tests were performed, with results indicating that tunnelling induced ground volumetric strains could influence the post-tunnelling loading response of piles.

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Section: Centrifuge Modelmentioning

confidence: 99%

Section: Centrifuge Modelmentioning

confidence: 99%

Section: Pile Load Distribution During Centrifuge Spin-upmentioning

confidence: 99%

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Centrifuge Study on the Influence of Tunnel Excavation on Piles in Sand

Song

Marshall

2020

J. Geotech. Geoenviron. Eng.

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“…The centrifuge strong box has inner width × height dimensions of 700 mm × 500 mm, with a depth of 150 mm, and the 'front' face is equipped with a transparent acrylic wall. Tunnel volume loss was implemented using a 90 mm diameter eccentric rigid boundary mechanical model tunnel which enables non-uniform radial displacements around the tunnel lining (typical for shallow tunnelling), with maximum soil displacement at the tunnel crown and no displacement at the tunnel invert (Song et al, 2018;Song and Marshall, 2020a). Two cameras were used to take images during the tests, and geoPIV-RG (Stanier et al, 2015) was used to track subsurface soil and protective wall movements.…”

Section: Experimental Set Upmentioning

confidence: 99%

Centrifuge application of fibre Bragg gratings: pile axial loads and wall bending moments

Song

Heron

et al. 2022

International Journal of Physical Modelling in Geotechnics

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One challenge for geotechnical centrifuge testing of soil–structure interaction problems is the reliable measurement of induced structural strains/forces. This paper presents a novel application of fibre Bragg grating (FBG) sensors for strain measurement within geotechnical centrifuge tests. FBG sensors have several advantages for centrifuge testing, in particular their small size and minimal self-weight. This paper gives an overview of recently developed installation and calibration procedures for FBG sensors within buried centrifuge model structures. The effect of thermal expansion/contraction of the materials (including both the fibre and structures) is considered and assessed. The precision and reliability of the FBG sensors are demonstrated using verification tests. The application of the FBG sensors is considered for two geotechnical problems, namely, pile jacking and a ‘retaining wall’ adjacent to a tunnel (acting as a protective wall to prevent an adjacent structure from tunnelling-induced ground movement). The results demonstrate that the FBG sensors can provide reliable measurements of pile axial strains/forces and protective wall bending moments. The paper provides evidence to support the routine adoption of FBG sensors for strain/force measurement of structures in geotechnical centrifuge modelling.

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“…In terms of experimental studies, Song and Marshall [24] believed that the choice of the model tunnel has an effect on the imparted tunnel boundary displacements and resulting ground deformations, and contrasting plane-strain centrifuge test results from experiments using a flexible membrane model tunnel with those from a newly developed eccentric rigid boundary mechanical model tunnel to quantitatively evaluate this effect. Loganathan et al [25] studied the deformation of the clay foundation caused by tunnel excavation and its effect on the adjacent pile foundation using three centrifugal model tests.…”

Section: Introductionmentioning

confidence: 99%

Analytical Study of Soil Displacement Induced by Twin Shield Tunneling in Semi‐Infinite Viscoelastic Ground

Shi

Rong

Wang

et al. 2020

Advances in Civil Engineering

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Effective measures are needed to strictly control soil displacement caused during the process of shield construction excavation for urban subway tunnels. When calculating the displacement of soil caused by loading or unloading, many previous analytical studies have assumed that the soil was a linear elastic body and ignored the viscosity of the soil. In this study, the Boltzmann viscoelastic model and the Mindlin basic solution were combined to consider the effects of the additional support pressures, the shield shell frictions, the grouting pressures, and the ground loss, and a three-dimensional viscoelastic solution for soil displacement caused by shield tunneling was derived. According to the calculation results of an example, the analytical solution was able to consider the asynchronous construction of the left and right tunnels and the mutual influence of the double shield tunnel. The rationality of the approach proposed in this study was verified by comparing the theoretical solution with the measured settlement values. In addition, the influence of differences in the viscoelastic parameters (the viscosity coefficient, the shear modulus of the elastic element, and the shear modulus of the viscous element) and the geometric parameters (the distance from the excavation surface, the calculated depth, and tunnel spacing) on soil displacement is discussed. The calculation method in this study provides a theoretical basis for predicting the three-dimensional soil deformation caused by shield tunneling, especially in soft clays.

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Centrifuge modelling of tunnelling induced ground displacements: pressure and displacement control tunnels

Cited by 29 publications

References 28 publications

Centrifuge Study on the Influence of Tunnel Excavation on Piles in Sand

Centrifuge Study on the Influence of Tunnel Excavation on Piles in Sand

Centrifuge application of fibre Bragg gratings: pile axial loads and wall bending moments

Analytical Study of Soil Displacement Induced by Twin Shield Tunneling in Semi‐Infinite Viscoelastic Ground

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