Physical model on effects of tunnelling towards single piles under zoned of influence

Abstract

Tunnel excavation usually will causes soil redistribution and settlement. Hence, for urban areas where large building used pile for foundation, tunnelling might affect the pile integrity. Engineers pose great role in order to correctly estimating the stress changes onto pile structures. It is particularly vital to estimate the tunnelling effects when new tunnels are to be built near an existing pile. Therefore, this paper presents a physical modelling to investigate the tunnel-pile-soil interaction. Sand box test with pile and tunnel model was developed to imitate the field condition. The laboratory testing conducted with constant parameter tunnel cover to tunnel diameter ratio of 2.5 with pile to tunnel distance of 1.5 of tunnel diameter. Two rate of tunnel excavation were carried out. Laboratory tests determined the longitudinal and transverse ground surface settlement induced by tunnelling, as well as the movement and induced bending moment on a single pile foundation. For validation, initial results were compared with previous findings and shows an agreement. Further test then conducted with higher tunnelling speed. With higher speed, it was found that surface settlements, pile movements and bending moment are more affected.