Axial response of short pile due to tunnelling-induced soil movement in soft clay

Abstract

Soil movements due to tunnelling work may induce severe stresses on the foundations supporting nearby structures. The situation is particularly severe for the cases of short piles supporting low-rise or old buildings with the pile toes located above the tunnel excavation elevation. In this study, centrifuge model tests were conducted to investigate the axial response of a single short pile located at various offset distances from the tunnel centreline with different ground volume losses in soft clay under undrained conditions. The test results reveal that the load-transfer pattern along the pile shaft changes with the pile offset distance away from the tunnel centreline. Three-dimensional finite-element analyses were then conducted to evaluate the effect of pile–soil relative stiffness on the performance of adjacent piles due to tunnelling. Finally, a method is proposed to provide a preliminary estimation of the maximum-induced axial force on short piles subject to tunnelling-induced soil movement.