Three-dimensional centrifuge modelling of tunnelling effects on pile group

摘要

Tunnels are often preferred for underground transportation systems in densely populated areas.rnIt is almost inevitable for tunnels to run close to some existing pile foundations in these areas. Since tunnellingrnactivities induce stress relief and soil movement in the ground, existing piles may suffer from additional axialrnand lateral forces, bending moments, settlements and lateral deflections. Most of the previous researches onrnthe responses of pile foundations due to tunnel construction were carried out under the plane strain condition.rnFull understanding of three-dimensional tunnel-soil-pile interaction has not been achieved. This paper describesrna three-dimensional centrifuge model test to investigate the responses of a pile group due to tunnel excavation.rnIn-flight tunnel advancement including four stages was simulated, with a volume loss of 1.3%. Duringrntunnel advancement, the ground surface settlement, the overall settlement and the tilting of the pile caprnwere recorded. Furthermore, the model piles were instrumented to capture bending moments along the entirernpile length. Based on these measurements, three-dimensional influence of tunnel construction on the existingrnpile group in various advancing stages is described and analysed.