Theoretical Solutions for Shield Tunneling induced Long term Settlements in Clays

Abstract:

Theoretical solutions for tunneling induced long term ground settlements in clays are presented by modifying displacement solutions of drained contraction of cavity based on the Sagaseta’s image technique and the Park’s displacement boundary condition. The proposed solutions are compared with quoted centrifuge tests， finite element simulation based on displacement controlled model (DCM) and field studies. The results indicate that for the prediction of long term surface settlements， the theoretical solutions under uncorrected boundary condition 1 deviate significantly from the centrifuge tests， while those under the remaining three boundary conditions are in good agreement with the centrifuge tests and finite element method， and boundary condition 2 is recommended as a conservative approach. Generally agreement of the predicted surface settlements can be seen with field observations.

Key words:cavity contraction; tunneling; long term settlements; clays