Evaluation of liner responses due to non-uniform tail void grouting pressure

ABSTRACT

Tail void grouting initially does facilitate the action of ground loads around the lower half of the liner and no excess pressure being accumulated. However, at a later stage (almost at the completion of grouting), grout pressure becomes non-uniformly distributed around grout injection holes especially on the upper half of the liner. In the present study, the boundary and loading conditions were simulated by using a series of finite element analyses. It aimed to explore the effects of such temporary non-uniform loading conditions on development of the liner internal forces. The results obtained for tunnel with diameter of 6.0 m were presented. It was found that there were critical locations where application of non-uniform grouting pressure could result in large amounts of bending moment and deformation. Those critical locations; about ±30° to ±50° from crown of the tunnel, were about the locations where actual grouting was injected in the field. The stiffness of sub-soil beneath the tunnel invert had minor effect on the amount of induced structural forces. However, ground coverage was more important. The results, though cannot fully represent complicated tail grouting behaviours, provided a simple analytical procedure for exploring the effects of tail void grouting on the segmental liner.

KEYWORDS:

• Word
• tail void grout
• tunnel liner
• finite element analysis

Acknowledgments

The authors would like to gratefully acknowledge the financial support provided by the Thailand Research Fund (TRF: RMU5180052) and by the Commission on Higher Education, Ministry of Education under Faculty Development Scholarship Program with the collaboration of AUN/SEED-Net and the Rachadaphiseksomphot Endowment Fund, part of the “Strengthen Chulalongkorn University Researcher’s Project”.

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

The authors would like to gratefully acknowledge the financial support provided by the Thailand Research Fund (TRF: RMU5180052) and by the Commission on Higher Education, Ministry of Education under Faculty Development Scholarship Program with the collaboration of AUN/SEED-Net and the Rachadaphiseksomphot Endowment Fund, part of the “Strengthen Chulalongkorn University Researcher’s Project”.