Lateral behaviour of a pile group due to side-by-side twin tunnelling in dry sand: 3D centrifuge tests and numerical modelling

Soomro, Mukhtiar Ali; Ng, Charles Wang Wai; Memon, Noor Ahmed; Bhanbhro, Riaz

doi:10.1016/j.compgeo.2018.04.010

Cited by 45 publications

(8 citation statements)

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“…Centrifuge modeling technique and model tests were also carried out to study the responses of single piles or piles groups subjected to tunneling. (Loganathan et al , 2000; Jacobsz et al , 2004; Ong et al , 2006; Chiang and Lee, 2007; Ng et al , 2013; Hong, 2015; Soomro et al , 2017, 2018; Leung et al , 2019; Sohaei et al , 2020; He et al , 2022). These experimental methods divulge some fundamental features of the problem.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional numerical analyses of pile responses to tunneling-induced ground movements in bilayer soil

Houhou

Amari

Belounar³

2022

WJE

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Purpose This paper aims to investigate the responses of single piles and pile groups due to tunneling-induced ground movements in a two-layered soil system. The analyses mainly focus on the additional single pile responses in terms of bending moment, lateral deflection, axial force, shaft resistance and pile settlement. Subsequently, a series of parametric studies were carried out to better understand the responses of single piles induced by tunneling. To give further understanding regarding the pile groups, a 2 × 2 pile group with two different pile head conditions, namely, free and capped, was considered. Design/methodology/approach Using the PLAXIS three-dimensional (3D) software, a full 3D numerical modeling is performed to investigate the effects of ground movements caused by tunneling on adjacent pile foundations. The numerical model was validated using centrifuge test data found in the literature. The relevance of the 3D model is also judged by comparison with the 2D plane strain model using the PLAXIS 2D code. Findings The numerical test results reveal that tunneling induces significant displacements and internal forces in nearby piles. The magnitude and distribution of internal forces depend mainly on the position of the pile toe relative to the tunnel depth and the distance between the pile and the vertical axis of the tunnel. As the volume loss increases from 1% to 3%, the apparent loss of pile capacity increases from 11% to 20%. By increasing the pile length from 0.5 to 1.5 times, the tunnel depth, the maximum pile settlement and lateral deflection decrease by about 63% and 18%, respectively. On the other hand, the maximum bending moment and axial load increase by about 7 and 13 times, respectively. When the pile is located at a distance of 2.5 times the tunnel diameter (Dt), the additional pile responses become insignificant. It was found that an increase in tunnel depth from 1.5Dt to 2.5Dt (with a pile length of 3Dt) increases the maximum lateral deflection by about 420%. Regarding the interaction between tunneling and group of piles, a positive group effect was observed with a significant reduction of the internal forces in rear piles. The maximum bending moment of the front piles was found to be higher than that of the rear piles by about 47%. Originality/value Soil is a complex material that shows differently in primary loading, unloading and reloading with stress-dependent stiffness. This general behavior was not possibly being accounted for in simple elastic perfectly plastic Mohr–Coulomb model which is often used to predict the behavior of soils. Thus, in the present study, the more advanced hardening soil model with small-strain stiffness (HSsmall) is used to model the non-linear stress–strain soil behavior. Moreover, unlike previous studies THAT are usually based on the assumption that the soil is homogeneous and using numerical methods by decoupled loadings under plane strain conditions; in this study, the pile responses have been exhaustively investigated in a two-layered soil system using a fully coupled 3D numerical analysis that takes into account the real interactions between tunneling and pile foundations. The paper presents a distinctive set of findings and insights that provide valuable guidance for the design and construction of shield tunnels passing through pile foundations.

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Section: Introductionmentioning

confidence: 99%

Three-dimensional numerical analyses of pile responses to tunneling-induced ground movements in bilayer soil

Houhou

Amari

Belounar³

2022

WJE

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“…Numerical models have also clearly made important contributions to developing our understanding of tunnel-pile and tunnel-pile-structure interactions. Many numerical investigations have made use of available centrifuge test data as a means of verifying the numerical models (Hong et al, 2015;Ng et al, 2015;Soomro et al, 2018;Li and Zhang, 2020;Cheng et al, 2007;Wang et al, 2020). The numerical analyses typically adopt pressure or displacement controlled methods to simulate the tunnel volume loss process.…”

Section: Introductionmentioning

confidence: 99%

“…In some instances, the mode of volume loss simulation is guided by the type of model tunnel used in the centrifuge tests against which the numerical models are compared; a fluid-filled flexible membrane model tunnel is arguably best suited to a pressure-controlled (or material softening (Li and Zhang, 2020)) simulation, whereas a displacing rigid-boundary model tunnel is well replicated by a displacement controlled simulation. There are studies which have adopted simulations which go against the above logic that have successfully demonstrated agreement between numerical and centrifuge test results (Cheng et al, 2007;Hong et al, 2015;Soomro et al, 2018;Wang et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Tunnel–piled structure interaction: Numerical simulation of hybrid centrifuge tests

Song

Marshall

2021

Computers and Geotechnics

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“…A comprehensive understanding of tunnel-bridge interaction is necessary to ensure safety and maintain bridge stability when tunneling below a bridge. Most recent studies of interaction between tunnels and surface structures have been concerned with the effects of tunnel excavation on existing overlying structures (Chen et al, 1999;Lee and Jacobsz, 2006;Cheng et al, 2007;Lee and Chiang, 2007;Yoo, 2013;Soomro et al, 2018), although there has been some research into dismantling temporary lining.…”

Section: Introductionmentioning

confidence: 99%

Effects on a Nearby Bridge of Dismantling Temporary Lining During Excavation of a Shallow-Buried Rectangular Tunnel

Gui-lin

Wen

et al. 2021

Front. Earth Sci.

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It is almost inevitable that when a tunnel is excavated in an urban area, it will pass under an existing bridge. During tunnel excavation, a temporary lining is installed and subsequently removed. However, dismantling temporary lining may affect the stability of a nearby bridge. A numerical model was created and tests were conducted on a large-scale physical model to investigate the effects of dismantling temporary lining on a nearby bridge structure. A novel method of modeling the restraining force at the top of a pier was introduced to make the model more accurate in representing the physical situation. Analysis of the results led to the following conclusions and suggestions. 1. The process of removing temporary lining can have a significant impact on surface settlement and structural deformation of the bridge. 2. The effect of removing the second half temporary lining is greater than that of removing the first half. The key range of the tunnel where this phenomenon is principally observed contains one section of tunnel ahead (i.e., in the direction of tunnel advance) of the bridge span and the two sections to the rear. 3. A 6 m–3 m–6 m mixed dismantling method is recommended for use in the key range, and a rigid cap-connection method is proposed to counteract the considerable effects of dismantling temporary lining.

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Lateral behaviour of a pile group due to side-by-side twin tunnelling in dry sand: 3D centrifuge tests and numerical modelling

Cited by 45 publications

References 47 publications

Three-dimensional numerical analyses of pile responses to tunneling-induced ground movements in bilayer soil

Three-dimensional numerical analyses of pile responses to tunneling-induced ground movements in bilayer soil

Tunnel–piled structure interaction: Numerical simulation of hybrid centrifuge tests

Effects on a Nearby Bridge of Dismantling Temporary Lining During Excavation of a Shallow-Buried Rectangular Tunnel

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