CENTRIFUGE MODEL STUDY OF TUNNEL-SOIL-PILE INTERACTION IN SOFT CLAY

Abstract

In urban areas, tunnels are often constructed close to existing buildings due to space constraints. During tunnelling, the ground around the tunnel often moves towards the tunnel opening. The resulting ground movements induce additional axial (settlement and axial force) and lateral (deflection and bending moment) responses on adjacent pile foundations. As a result, the foundations may not be able to resist the loads induced by tunnelling nearby. In this thesis, the results of a series of centrifuge model tests conducted to investigate the effects of tunnelling on single piles and pile groups in soft clay are presented. The effects of volume loss, effects of pile tip and head condition, effects of pile length, effects of pile-to-tunnel distance, effects of floating and end-bearing pile groups, effects of size of pile group and effects of pile groups with capped-head and fixed-head conditions due to tunnelling are also examined. In addition, the observed pile behaviours are evaluated against the measured free field soil movements due to tunnelling using Particle Image Velocimetry technique (PIV) technique.