<abstract xmlns="http://www.w3.org/1999/xhtml"><p>In urban areas, the control of ground surface settlement is an important issue during shield tunnel-boring machine (TBM) tunneling. These ground movements are affected by many machine control parameters. In this article, a finite difference (FD) model is developed using Itasca FLAC-3D to numerically simulate the whole process of shield TBM tunneling. The model simulates important components of the mechanized excavation process including slurry pressure on the excavation face, shield conicity, installation of segmental lining, grout injection in the annular void, and grout consolidation. The analysis results from the proposed method are compared and discussed in terms of ground movements (both vertical and horizontal) with field measurements data. The results reveal that the proposed 3D simulation is sufficient and can reasonably reproduce all the operations achieved by the TBM. In fact, the results show that the TBM parameters can be controlled to have acceptable levels of surface settlement. In particular, it seems that moderate face pressure can reduce ground movement significantly and, most importantly, can prevent the occurrence of face-expected instability when the shield crosses very weak soil layers. The shield conicity has also an important effect on ground surface settlement, which can be partly compensated by the grout pressure during tail grouting. Finally, the injection pressure at the rear of the shield significantly reduces the vertical displacements at the crown of the tunnel and, therefore, reduces the settlement at the ground surface.</p></abstract>

In urban areas, the control of ground surface settlement is an important issue during shield tunnel-boring machine (TBM) tunneling. These ground movements are affected by many machine control parameters. In this article, a finite difference (FD) model is developed using Itasca FLAC-3D to numerically simulate the whole process of shield TBM tunneling. The model simulates important components of the mechanized excavation process including slurry pressure on the excavation face, shield conicity, installation of segmental lining, grout injection in the annular void, and grout consolidation. The analysis results from the proposed method are compared and discussed in terms of ground movements (both vertical and horizontal) with field measurements data. The results reveal that the proposed 3D simulation is sufficient and can reasonably reproduce all the operations achieved by the TBM. In fact, the results show that the TBM parameters can be controlled to have acceptable levels of surface settlement. In particular, it seems that moderate face pressure can reduce ground movement significantly and, most importantly, can prevent the occurrence of face-expected instability when the shield crosses very weak soil layers. The shield conicity has also an important effect on ground surface settlement, which can be partly compensated by the grout pressure during tail grouting. Finally, the injection pressure at the rear of the shield significantly reduces the vertical displacements at the crown of the tunnel and, therefore, reduces the settlement at the ground surface.

Slurry shield tunneling in soft ground. Comparison between field data and 3D numerical simulation

Studia Geotechnica et Mechanica

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

In urban areas, the control of ground surface settlement is an important issue during shield tunnel-boring machine (TBM) tunneling. These ground movements are...

Layer	Depth -	Shear (G)	Bulk (K)	Weight (g)	Cohesion (c’)	Friction (j’)	Dilatancy (y’)
	m	MPa	MPa	kN/m³	KPa	°	°
Fill	0–7	2.92	7.8	18	30	30	17
Beige silt	7–10	2.74	7.3	19.5	12	33	20
Ocher silt	10–13	2.74	7.3	21	15	25	14
Grey clay	13–15	1.57	4.2	16.5	35	27	15
Grey sand	15–17.5	10.50	28	21	5	35	21
Purplish clay	17.5–20	5.16	13.8	18.5	35	27	15
Sand and gravel	20–50	10.50	28	21	0	34	20

Grout	Unit weight (kN/m³)	Young’s modulus (MPa)	Poisson ratio (-)	Bulk modulus (K) (MPa)	Shear modulus (G) (MPa)	K/G (-)
Fluid state	18	5	0.495	166.7	1.7	99.7
Solid state	18	30	0.20	16.7	12.5	1.3

Slurry shield tunneling in soft ground. Comparison between field data and 3D numerical simulation

Article Category: Research Article

Published Online: Sep 30, 2019

Page range: 115 - 128

Received: Dec 28, 2018

Accepted: May 07, 2019

DOI: https://doi.org/10.2478/sgem-2019-0003

Keywords
Shield tunneling, soil–structure interaction, 3D numerical simulation, back analysis, settlement

© 2019 Mohammed Beghoul , Rafik Demagh, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

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Figure 16

Mohr–Coulomb parameters.

The properties of grout in modeling.

Tunnel parameters.

Slurry shield tunneling in soft ground. Comparison between field data and 3D numerical simulation

Article Category: Research Article

Published Online: Sep 30, 2019

Page range: 115 - 128

Received: Dec 28, 2018

Accepted: May 07, 2019

DOI: https://doi.org/10.2478/sgem-2019-0003

KeywordsShield tunneling, soil–structure interaction, 3D numerical simulation, back analysis, settlement

© 2019 Mohammed Beghoul , Rafik Demagh, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Mohr–Coulomb parameters.

The properties of grout in modeling.

Tunnel parameters.

Keywords
Shield tunneling, soil–structure interaction, 3D numerical simulation, back analysis, settlement