Numerical investigation on impact of excavations in influence zone of existing MRT tunnels

ABSTRACT

Due to a high demand of space utilisation in metropolitan area, the existing tunnels, which are normally used for underground transportation and service utilities, can be suffered from the impacts caused by the adjacent constructions. In general, the protection zone of a tunnel is developed based on the assumption of shear plane of soil, rather than the soil–structure interaction. The assessment of the impacts of new construction nearby the existing tunnel is thus essential for improving the protection zone. 3D finite-element analyses are conducted for the case of the mass rapid transit (MRT) tunnels in soft ground. The impacts on the MRT tunnels from two possible underground construction cases (i.e. open cut and pipe jacking) are investigated in terms of tunnel deformations and changes in tunnel lining moment. The advantages of using 3D analysis are to model the realistic soil–structure interactions and to observe the multidirectional impacts on MRT tunnels. The results show that the bending moments increased by both open cut and pipe jacking construction activities are relatively small. For the tunnel deformations, most cases are sufficiently secure, but only in some cases, the deformations of tunnel lining almost reach the limit of 6 mm. However, it is highly recommended that they are still required to numerically examine in case by case

KEYWORDS:

• Finite-element modelling
• tunnelling
• long-term analysis
• influence zone
• Bangkok subsoil

Acknowledgments

This research was supported by the National Research Council of Thailand (NRCT): NRCT5-RSA63001-05. The third author (Veerayut Komolvilas) acknowledges the financial support from the Office of the Permanent Secretary, Ministry of Higher Education, Science, Research and Innovation: Grant No. RGNS 63-019. The authors would like to thank Mr Chhunla Chheng and Mr Sarun Bamrungchat for providing useful information throughout the research. The authors especially thank Dr Weeradetch Tanapalungkorn for his kind help on graphical visualisation.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability statement

All data generated or analysed during this study are included in this published article.

Ethical approval

This article does not contain any studies with human participants or animals performed by any of the authors. It also has not been published by another journal.

CRediT author statement

Napachai Muenpetch: Investigation, Formal analysis, Visualisation. Suraparb Keawsawasvong: Visualisation, Supervision, Writing – Original Draft. Veerayut Komolvilas: Investigation, Supervision, Writing – Original Draft. Suched Likitlersuang: Conceptualisation, Supervision, Writing – Review & Editing, Project administration, Funding acquisition.

Additional information

Funding

The work was supported by the National Research Council of Thailand [NRCT5-RSA63001-05]; Office of the Permanent Secretary, Ministry of Higher Education, Science, Research and Innovation [RGNS 63-019.]