The influence of tunnelling and deep excavation on piled foundations

摘要

The paper addresses the effects of tunnelling and deep excavations on piled foundations. Itrnfocuses particularly on cases where tunnels are constructed beneath pile toes; it also discusses deep excavationsrnadjacent to buildings for which the depth of excavation extends significantly below the piles. Case historiesrnare reviewed and some new ones are presented. For friction piles the settlement was generally observed to bernsimilar to the settlement of the ground surface at the position of the pile head. Some results of recent centrifugernmodelling of tunnelling beneath bored piles in stiff clays are presented; these elucidate the detailed behaviourrnof piles subject to tunnel volume loss, particularly in relation to settlement, load distribution and shaft friction.rnComments are made on numerical modelling, analytical methods and empirical methods used in practice. Fieldrnobservations of the effects of deep excavations on piled buildings are also presented.