Tunnelling Induced ground settlement considering soil variability

Ground settlement need to be predicted well so that necessary precautionary measures could be adopted. Ground deformation behavior due to tunnel construction in inhomogeneous soil has been studied in the past few decades by many researchers. When tunnel-induced ground, settlement is predicted by considering average soil properties, it is likely to miss the true settlement characteristics and failure mechanism due to the inherent heterogeneity of the ground. In this paper, spatial variability of the ground is considered in the numerical analysis to simulate the ground settlement. A numerical model is developed using the Finite-Difference based numerical code FLAC3D to simulate tunnel construction with earth pressure balance (EPB) TBMs for a case study. Both 2D and 3D random fields are simulated in the numerical model. Results are systematically compared with some of the empirical and analytical methods for predicting ground settlement. Spatial distribution is found to have a significant effect on surface settlements and overall ground behavior.