# An Improved 3D Finite Difference Model for Simulation of Double Shield TBM Tunnelling in Heavily Jointed Rock Masses: the DXL Tunnel Case

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## Introduction

The past few decades have witnessed an increasing utilization of TBMs for long and deep tunnels. Compared to drill and blast method, TBMs contribute significant savings in construction time and costs. According to Barla and Pelizza (2000), hard rock TBMs can be classified into three types: open type TBMs, single shield TBMs and double shield TBMs (DS TBMs). Owing to their suitability for different rocks, DS TBMs are being increasingly considered for use in rock tunnelling projects under high groundwater pressure and in deep tunnels (Hasanpour et al. 2014). However, DS TBMs may get stuck in squeezing grounds or adverse geological conditions. It is a time-consuming, costly, unsafe and slow labour intensive work to release the machine by manual excavation. Thus, the possibility of machine entrapment in deep tunnels is the main disadvantage of DS TBMs (Farrokh and Rostami 2009).

There are many factors that may result in machine entrapment, such as squeezing rock conditions...

## Keywords

Machine entrapment Shield jamming Ground collapse Double shield TBM Heavily jointed rock masses Ubiquitous-joint model## List of symbols

*F*_{f}Thrust force to overcome friction (MN)

*F*_{n}Cutterhead thrust force (MN)

*F*_{r}Required thrust force (MN)

*R*Tunnel radius (m)

- \({\sigma _H}\)
Major horizontal principal stress (MPa)

- \({\sigma _h}\)
Minor horizontal principal stress (MPa)

- \({\sigma _v}\)
Vertical stress (MPa)

- \({\sigma _{xx}}\)
*X*-component of normal stress (MPa)- \({\sigma _{yy}}\)
*Y*-component of normal stress (MPa)- \({\sigma _{zz}}\)
*Z*-component of normal stress (MPa)- \({\bar {\sigma }_{xx}}\)
*X*-component of average normal stress (MPa)- \({\bar {\sigma }_{zz}}\)
*Z*-component of average normal stress (MPa)- \(\sum {\sigma _{xx}}\)
Sum of

*X*-component of normal stresses (MPa)- \(\sum {\sigma _{zz}}\)
Sum of

*Z*-component of normal stresses (MPa)

## Notes

### Acknowledgements

The authors are grateful to Mr. Amila Chaminda Wickrama Arachchi for his linguistic assistance. Special thanks go to Prof. Giovanni Barla and the anonymous reviewer for their constructive comments.

## References

- Barla G (2002) Tunnelling under squeezing rock conditions. In: Kolymbas D (ed) Eurosummer-School in Tunnel MechanicsLogos Verlag, Berlin, pp 169-268Google Scholar
- Barla G (2013) Is 3D modeling of TBM excavation in squeezing rock a feasible and useful design tool? In: Flora M, Jager M, Wilfinger N (eds) Luis Vigl Festschrift zum 60. GeburtstagGoogle Scholar
- Barla G, Pelizza S (2000) TBM tunnelling in difficult ground conditions. In: Proceedings of GeoEng 2000—Proceedings of the international conference on geotechnical and geological engineering, Melbourne, November 19–24, 2000. Technomic Publishing Company, Lancaster, pp 329–354Google Scholar
- Barla G, Zhao K, Janutolo M (2011) 3D advanced modelling of TBM excavation in squeezing rock condition. In: Proceedings of first Asian and ninth Iranian tunnel symposium, Tehran, IranGoogle Scholar
- Farrokh E, Rostami J (2009) Effect of adverse geological condition on TBM operation in Ghomroud tunnel conveyance project. Tunn Undergr Space Technol 24(4):436–446CrossRefGoogle Scholar
- Gong Q, Yin L, Ma H, Zhao J (2016) TBM tunnelling under adverse geological conditions: an overview. Tunn Undergr Space Technol 57:4–17CrossRefGoogle Scholar
- Hasanpour R (2014) Advance numerical simulation of tunnelling by using a double shield TBM. Comput Geotech 57(2):37–52CrossRefGoogle Scholar
- Hasanpour R, Rostami J, Ünver B (2014) 3D finite difference model for simulation of double shield TBM tunnelling in squeezing grounds. Tunn Undergr Space Technol 40(2):109–126CrossRefGoogle Scholar
- Home L (2016) Hard rock tbm tunnelling in challenging ground: developments and lessons learned from the field. Tunn Undergr Space Technol 57:27–32CrossRefGoogle Scholar
- Munjiza A (2004) The combined finite-discrete element method. John Wiley and Sons, Ltd., LondonCrossRefGoogle Scholar
- Ramoni M, Anagnostou G (2010) Tunnel boring machines under squeezing conditions. Tunn Undergr Space Technol Inc Trenchless Technol Res 25(2):139–157CrossRefGoogle Scholar
- Vlachopoulos N, Diederichs MS (2009) Improved longitudinal displacement profiles for convergence confinement analysis of deep tunnels. Rock Mech Rock Eng 42(2):131–146CrossRefGoogle Scholar
- Zhao K, Janutolo M, Barla G (2012) A completely 3D model for the simulation of mechanized tunnel excavation. Rock Mech Rock Eng 45(4):475–497CrossRefGoogle Scholar
- Zhao K, Janutolo M, Barla G et al (2014) 3D simulation of TBM excavation in brittle rock associated with fault zones: the Brenner Exploratory Tunnel case. Eng Geol 181:93–111CrossRefGoogle Scholar
- Zhao K, Bonini M, Debernardi D et al (2015) Computational modelling of the mechanised excavation of deep tunnels in weak rock. Comput Geotech 66:158–171CrossRefGoogle Scholar
- Itasca (2012) FLAC3D Fast Lagrangian analysis of continua in 3D dimensions. User’s guideGoogle Scholar
- Itasca (2013) 3DEC 3 Dimensional distinct element code. User’s guideGoogle Scholar