2021 Volume 77 Issue 1 Pages 76-91
Safe and cost-effective excavation of mountain tunnels requires accurate prediction of geotechnical condition ahead of the tunnel face and preventive auxiliary methods or appropriate support members should be adopted correspondingly. Authors have so far developed a method to predict the change in ground stiffness ahead of the tunnel face by means of inclination monitoring which can be applied without any hindrance to the construction. Applicability and validity of the method have been verified through numerical simulation and field measurement tests. This study performs parametric numerical simulations in which ground stiffness at the face under excavation and ahead of the face, and tunnel overburden are considered as variables in order to clarify the geotechnical condition required for the application of the proposed prediction method. The study also discusses a quantitative estimation method for the tunnel crown settlement by measured inclination. This leads to further effective use of ground prediction results in which allowable deformation volume and appropriate auxiliary methods required can be determined beforehand. Effectiveness of the estimation method is investigated through the post-evaluation of field measurement data.
