Centrifuge modelling of tunnelling with forepoling

Divall, S.; Taylor, R.N.; Xu, Mingwei

doi:10.1680/jphmg.15.00019

Cited by 8 publications

(10 citation statements)

References 7 publications

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“…This is an obvious indication that the arrangements of forepoles may contribute to reinforce the soil around the excavation. A Pearson correlation analysis of measured and predicted values of Eur and Su, especially from the tests results performed by Divall et al (2016), showed a correlation of r = 0.6149, which indicates a moderate tendency for correlation. The lack of a strong correlation might be attributed to the fact that the soil was artificially improved by the addition of forepoles.…”

Section: Analysis Of Centrifuge Testsmentioning

confidence: 94%

Estimating settlements due to tunnel boring machine excavation

Rattia

Divall

Gitirana

et al. 2023

Proceedings of the Institution of Civil Engineers - Geotechnica

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Soft-ground Tunnel Boring Machines (TBM) are the preferred solution for construction of long tunnels and linear infrastructure assets, especially in urban areas. TBMs allow the control of tunnel face stability, minimizing effects on the surrounding ground. Unfortunately, the existing methods for the assessment of ground surface movements due to TBM tunnelling either utilise complex and computationally expensive numerical analyses or rely on simplistic volume loss theories, which do not consider characteristics of the ground and TBM operation. This paper presents a simple formulation to estimate the immediate surface settlement due to the applied TBM support pressure, based on an analogy with the hyperbolic behaviour of stress-strain curves of soils. The maximum surface settlement and volume loss were the variables chosen to describe the ground movement while the TBM face support pressure describes the tunnel internal support pressure. Uncertainties due to the inherent variability of geotechnical parameters were also considered, resulting in definition of lower and upper boundaries. Data from a series of centrifuge test results, with and without tunnel face reinforcement by forepoles and a real scale TBM case study were used to validate the proposed model. The analyses show that the proposed model adequately represented the observed settlement data.

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Section: Analysis Of Centrifuge Testsmentioning

confidence: 94%

Estimating settlements due to tunnel boring machine excavation

Rattia

Divall

Gitirana

et al. 2023

Proceedings of the Institution of Civil Engineers - Geotechnica

Self Cite

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“…The centrifugal model test is a proven approach and has been widely applied in the field of geotechnical engineering testing. In the early stage, Schofield used a centrifuge to analyze geotechnical problems [17][18][19][20][21][22][23][24][25][26][27], then the centrifuge tests were gradually applied to all aspects of geotechnical engineering [18][19][20][21][22][23]. Also, the centrifuge was used for tunnel analysis [24][25][26].…”

Section: Introductionmentioning

confidence: 99%

“…Also, the centrifuge was used for tunnel analysis [24][25][26]. The true stress conditions of a metro tunnel can be modeled by adjusting the centrifugal acceleration [27]. However, different collapsible conditions of the metro tunnel caused by foundation soaking cannot be well simulated in the currently CTE [21,[28][29][30][31] due to its inherent limitations.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Loess Soaking Induced Impacts on a Metro Tunnel Using a Water Soaking System in Centrifuge

et al. 2019

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The collapsibility is one of the key properties for loess. Harmful impacts on the metro tunnels could be obviously subjected to the soaking collapsibility in collapsible loess. However, loess soaking cannot be effectively modeled by the existing centrifugal test equipment (CTE) due to its inherent limitations. In the present paper, a water soaking system (WSS) was improved based on the existing CTE for simulating various loess soaking conditions. The WSS was made of a water storage subsystem and a water distribution subsystem. Some tests were conducted to show the capability of the improved WSS in centrifugal model tests firstly, then it was used to carry out centrifugal model tests on a metro tunnel under full-range and half-range foundation soaking conditions with different soaking depths. The impacts of various soaking conditions on the mechanical properties of the metro tunnel were discussed in detail.

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“…Xie et al [18] analyzed the impacts of the pipe roofs on the deformation mechanism of the dry sand soil; the whole process of deformation development was studied in their research. Other authors [19][20][21] have studied the influence of design parameters on the performance of pipe roofs research. In their study, different aspects such as the installation angle, diameter and transverse spacing of pipe roofs were considered.…”

Section: Introductionmentioning

confidence: 99%

Displacement Characteristics of Shallow-Buried Large-Section Loess Tunnel with Different Types of Pre-Supports: A Case Study of New Badaling Tunnel

et al. 2019

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Three-bench seven-step excavation method (TSEM) has been widely used in large-section loess tunnels for high-speed railway in China. As the most commonly applied pre-supports, pipe roofs and leading ductules are broadly used in the ground reinforcement of loess tunnels. Their application is to ensure face stability and prevent tunnel collapse during construction. This study focused on the impacts of the TSEM on the ground surface settlement (GSS), as well as the tunnel displacement characteristics for the high-speed railway tunnels with large cross-sections in loess ground. Furthermore, the reinforcement effects of the two kinds of pre-supports were compared in this study. In-situ tests for a total of 12 sections were conducted to reveal the GSSs and displacement characteristics for the shallow-buried large-section loess tunnels. The monitoring results showed that the excavation process plays a significant role on the GSSs and tunnel displacements. A maximum value was observed for the tunnel displacement rate at the excavation of the upper and middle benches, where the face instability or collapse were prone to occur. The GSS trough curves were deviated to the early excavation side, with no conformation to the Gauss distribution. After a series of comparisons, we concluded that the pre-reinforcement effect of the pipe roof is better than that of the leading ductule for the loess tunnels.

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Centrifuge modelling of tunnelling with forepoling

Cited by 8 publications

References 7 publications

Estimating settlements due to tunnel boring machine excavation

Estimating settlements due to tunnel boring machine excavation

Modeling of Loess Soaking Induced Impacts on a Metro Tunnel Using a Water Soaking System in Centrifuge

Displacement Characteristics of Shallow-Buried Large-Section Loess Tunnel with Different Types of Pre-Supports: A Case Study of New Badaling Tunnel

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