3D numerical investigation of the coupled interaction behavior between mechanized twin tunnels and groundwater – A case study: Shiraz metro line 2

To use urban underground space more efficiently is a research hotspot of urban underground development. Compared with conventional circular tunnels, quasirectangular tunnels have the characteristics of larger space utilization and higher economic benefits, gradually used in urban rail engineering in recent years. But the ground disturbance induced by the quasirectangular tunneling needs further researches. This paper derives the calculation formula of the additional stress of existing shield tunnel below caused by the quasirectangular shield tunneling by mirror image method and Mindlin solution. The existing shield tunnel is simplified as an elastic foundation short beam connected by tensile springs and shear springs. This paper establishes the energy-deformation coupling equation by principle of minimum potential energy so that the disturbance induced by quasirectangular tunneling to the existing shield tunnel below can be analyzed. The FEM is established with the actual engineering as the background. It is by comparing the numerical simulation results and field monitoring data that the theoretical prediction formula is verified. The research results show that the theoretical calculation results consist highly with numerical simulation results and field monitoring data, verifying practicality of formulas in this paper. Calculation results of shear stagger model are more accurate, which can be also used to analyze the staggered and splayed amount between segments. As the tunnel construction proceeds, uplift deformation, segment stagger, shear force, and segment splay of existing shield tunnel gradually increase, which are symmetrical about the central axis of new tunnel. After the shield machine passes through the central axis of the existing shield tunnel for 20 meters, stable disturbance to the existing shield tunnel occurs. Stagger amount and shear force between segments reach the minimum at the position with maximum uplift deformation of existing shield tunnel and reach the maximum at inflection point of the uplift deformation curve.

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“…D is diameter of existing shield tunnel. k is foundation bed coefficient, which is calculated by reference [16][17][18]…”

Section: Total Potential Energy Of Existingmentioning

confidence: 99%

Analysis of Shear Stagger Deformation of Existing Shield Tunnel below Induced by Quasirectangular Shield Tunneling

et al. 2023

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“…Additionally, in each model, a different load is applied (20,70, and 130 kPa) 130 kPa is assumed in the densely populated area, while 70 kPa is assumed in the no populated area of Seville, and 20 kPa is recommended for locations with the low of buildings and traffic. To this end, it has been assumed that this method simpli creation of a model [53]. Two distinct methods are considered when determin weight of the buildings [29,57].…”

Section: Dimensions Of the Model And Boundary Conditionsmentioning

confidence: 99%

“…Likewise, groundwater conditions must not be overlooked as a clear influencing factor. Shivaei et al [53] studied both the drainage condition of the grout layer in mechanised excavation and the difference in surface settlement by changing the soil permeability and water table level. They concluded that with lowering the water table, the surface settlement decreased.…”

Section: Introductionmentioning

confidence: 99%

Numerical Model Validation for Detection of Surface Displacements over Twin Tunnels from Metro Line 1 in the Historical Area of Seville (Spain)

et al. 2022

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In order to solve connectivity problems in metropolitan areas, the development of underground metro lines constitutes an unquestionable requirement. However, the construction work thereof encounters unfavourable circumstances when surface excavations must be carried out that cross historical areas of the city, due to the need to control surface movements. The design of the metro in the city of Seville (Spain) from 2004 to 2006 provides a representative example of this situation and triggered major upheavals that exerted repercussions on historical buildings. For these reasons, the excavation stages of Line 1 of this metro have been simulated by numerical methods using FLAC3D software and validated with the results provided by the real conditions. Consequently, various surface settlements have been evaluated by taking not only variates of the main parameters that characterise the soil of Seville, but also of the various load situations and excavation conditions. Notable results have been achieved through calibration of 54 variants of the same model corresponding to Line 1, and their comparison with the real results obtained in nine critical areas of the itinerary. The results obtained have made it possible to determine the effects of excavation on the subsoil of the city of Seville with great accuracy, since the percentage error of calculated vertical surface movements varies from 0.1% to 5.3%.

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“…The real average advance rates of TBM-EPB of the lower and upper tunnels when passing the investigated section (0+980) are 4.8 and 2.99 meters per day. Assuming that it takes half a day for injected grout to reach its hardened phase (Shivaei et al, 2020), the grouting pressure was eliminated after installing two lining rings. Beyond this length, hardened grout was simulated through volume elements with elastic characteristics.…”

Section: Numerical Simulationmentioning

confidence: 99%

“…Interactions between closely spaced tunnels were studied in the literature using several approaches: physical model testing (Kim et al, 1998;Chapman et al, 2007;Ng. et al, 2013;Lu et al, 2019;Lu et al, 2019;Tran and Hiroshi, 2020), field observations (Suwansawat and Einstein, 2007;Chen et al, 2011;Ocak, 2013), empirical/analytical methods (Wang et al, 2003;Suwansawat and Einstein, 2007;Yang and Wang, 2011;Wang et al, 2018, Zhang et al, 2018Zhang et al, 2020) and numerical modeling (Ercelebi et al, 2011;Hasanpour et al, 2012;Mirhabibi and Soroush, 2013;Do et al, 2014a;Chakeri and Unver, 2014;Chakeri et al, 2014, Janin et al, 2015Sahoo and Kumar, 2018;Zhao et al, 2019;Shivaei et al, 2020;Ly et al, 2021). Most studies in the literature focused on the effect of the tunnel distance, relative position of tunnels, tunnel depth, and soil properties on the stability of tunnel lining, surrounding ground, and adjacent structures.…”

Section: Introductionmentioning

confidence: 99%

A numerical investigation of the impact of shield machine’s operation parameters on the settlements above twin stacked tunnels - A case study of Ho Chi Minh urban railway Line 1

Anh¹,

Dias²,

Dang³

2021

Vietnam J. Earth Sci.

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Three-dimensional ﬁnite difference calculations are proposed to investigate the influence of operation parameters of the shield machines during twin stacked tunnel excavation on the surface settlements. The numerical model is validated by experimental data obtained from Hochiminh’s metro line 1 project, used as a reference case in this study. The parametric study focuses on the influence of the face support pressure, the grouting pressure, and the shield’s length. The numerical results indicated that a decrease does not always follow an increase in surface settlements' face and grouting pressure. A shorter shield machine causes smaller surface settlements to develop over single lower and twin stacked tunnels.

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3D numerical investigation of the coupled interaction behavior between mechanized twin tunnels and groundwater – A case study: Shiraz metro line 2

Cited by 26 publications

References 28 publications

Analysis of Shear Stagger Deformation of Existing Shield Tunnel below Induced by Quasirectangular Shield Tunneling

Analysis of Shear Stagger Deformation of Existing Shield Tunnel below Induced by Quasirectangular Shield Tunneling

Numerical Model Validation for Detection of Surface Displacements over Twin Tunnels from Metro Line 1 in the Historical Area of Seville (Spain)

A numerical investigation of the impact of shield machine’s operation parameters on the settlements above twin stacked tunnels - A case study of Ho Chi Minh urban railway Line 1

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